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1

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

2

Fuel Effects on Gas Turbine Combustion.  

National Technical Information Service (NTIS)

This program is an analytical study correlating fuel properties and engine design and operating parameters with engine combustion performance and hot section (combustor and turbine) durability. Standard fuel specification data and fuel composition data ar...

A. H. Lefebvre

1983-01-01

3

Combustion gas properties. 2: Natural gas fuel and dry air  

NASA Technical Reports Server (NTRS)

A series of computations has been made to produce the equilibrium temperature and gas composition for natural gas fuel and dry air. The computed tables and figures provide combustion gas property data for pressures from 0.5 to 50 atmospheres and equivalence ratios from 0 to 2.0. Only samples tables and figures are provided in this report. The complete set of tables and figures is provided on four microfiche films supplied with this report.

Wear, J. D.; Jones, R. E.; Trout, A. M.; Mcbride, B. J.

1985-01-01

4

Fuel Effects on Gas Turbine Combustion Systems.  

National Technical Information Service (NTIS)

The effects of variations in properties and characteristics of liquid hydrocarbon-base fuels in gas turbine engine combustors was investigated. Baseline fuels consisted of military-specification materials processed from petroleum and shale oil. Experiment...

S. A. Mosier

1984-01-01

5

Pollutants from Methane Fueled Gas Turbine Combustion.  

National Technical Information Service (NTIS)

The air pollution characteristics of a model gas turbine type combustor using methane as fuel were studied in this investigation. Detailed information regarding gas compositions at various locations within the combustor and direct measurement of temperatu...

P. G. Parikh R. F. Saw A. L. London

1971-01-01

6

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

7

Experimental study of gas turbine combustion with elevated fuel temperatures  

NASA Astrophysics Data System (ADS)

Many thermal management challenges have developed as advancements in gas turbine engine designs are made. As the thermal demands on gas turbine engines continue to increase, the heat sink available in the combustor fuel flow becomes more attractive. Increasing the temperature of fuel by using it as a heat sink can lead to higher combustion efficiency due to the increase in flow enthalpy and improved vaporization of the heated fuel. Emissions levels can also be affected by using heated fuels with the levels of carbon monoxide and unburned hydrocarbons tending to decrease while the amount of the oxides of nitrogen tends to increase. Although there are several benefits associated with using heated fuels in gas turbine engines, some problems can arise from their use including combustion instabilities, flashing within the fuel injector, and fuel coking or deposit formation within the fuel system. Various deoxygenation methods have been created to address the coking problem seen when using heated fuels. In the Gas Turbine Test Cell of the High Pressure Laboratory at Purdue University's Maurice J. Zucrow Laboratories, a 5 MW combustion rig was developed to complete combustion test with heated fuels. The facility's supply systems including heated air, jet fuel, cooling water, and nitrogen were designed and integrated to produce simulated engine conditions within the combustion rig. Heating capabilities produced fuel temperatures ranging up to 600 deg F. Testing was completed with two fuel deoxygenation methods: nitrogen sparging and catalytic deoxygenation. Results from the testing campaign included conventional pressure, temperature, and fuel property measurements; however, the most important measurements were the emissions samples that were analyzed for each test condition. Levels of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen were determined as well as the combustion efficiency calculated from these emissions measurements. The trends in emissions and performance from the increase in fuel temperature will be discussed. In addition, high frequency pressure data were recorded during testing to monitor combustion instabilities. Fuel samples were also taken and analyzed to document the changes in the volatile composition of the fuel from the two deoxygenation methods. The testing campaign was extremely successful. All project objectives were met with the heated fuel testing campaign. The combustion rig was run safely with fuel temperature up to 600 deg F, allowing the effects of elevated fuel temperatures on the performance and emissions of a gas turbine combustor to be evaluated as planned.

Wiest, Heather K.

8

Combustion of coal gas fuels in a staged combustor  

NASA Technical Reports Server (NTRS)

Gaseous fuels produced from coal resources generally have heating values much lower than natural gas; the low heating value could result in unstable or inefficient combustion. Coal gas fuels may contain ammonia which if oxidized in an uncontrolled manner could result in unacceptable nitrogen oxide exhaust emission levels. Previous investigations indicate that staged, rich-lean combustion represents a desirable approach to achieve stable, efficient, low nitrogen oxide emission operation for coal-derived liquid fuels contaning up to 0.8-wt pct nitrogen. An experimental program was conducted to determine whether this fuel tolerance can be extended to include coal-derived gaseous fuels. The results of tests with three nitrogen-free fuels having heating values of 100, 250, and 350 Btu/scf and a 250 Btu/scf heating value doped to contain 0.7 pct ammonia are presented.

Rosfjord, T. J.; Mcvey, J. B.; Sederquist, R. A.; Schultz, D. F.

1982-01-01

9

Toward the Impact of Fuel Evaporation-Combustion Interaction on Spray Combustion in Gas Turbine Combustion Chambers. Part I: Effect of Partial Fuel Vaporization on Spray Combustion  

Microsoft Academic Search

\\u000a This work aims at investigating the impact of the interaction between evaporation process and combustion on spray combustion\\u000a characteristics in gas turbine combustion chambers. It is subdivided into two parts. The first part studies how the evaporation\\u000a process affects the behavior of partially pre-vaporized spray combustion. The second part attempts to answer the question\\u000a how the fuel evaporation process behaves

Amsini Sadiki; W. Ahmadi; Mouldi Chrigui; J. Janicka

10

Fuel effects on gas turbine combustion-ignition, stability, and combustion efficiency  

Microsoft Academic Search

An analytical study is made of the substantial body of experimental data acquired during recent Wright-Patterson Aero Propulsion Laboratory sponsored programs on the effects of fuel properties on the performance and reliability of several gas turbine combustors, including J79-17A, J79-17C (Smokeless), F101, TF41, TF39, J85, TF33, and F100. Quantitative relationships are derived between certain key aspects of combustion, notably combustion

A. H. Lefebvre

1985-01-01

11

Fuel Flexible Combustion Systems for High-Efficiency Utilization of Opportunity Fuels in Gas Turbines  

SciTech Connect

The purpose of this program was to develop low-emissions, efficient fuel-flexible combustion technology which enables operation of a given gas turbine on a wider range of opportunity fuels that lie outside of current natural gas-centered fuel specifications. The program encompasses a selection of important, representative fuels of opportunity for gas turbines with widely varying fundamental properties of combustion. The research program covers conceptual and detailed combustor design, fabrication, and testing of retrofitable and/or novel fuel-flexible gas turbine combustor hardware, specifically advanced fuel nozzle technology, at full-scale gas turbine combustor conditions. This project was performed over the period of October 2008 through September 2011 under Cooperative Agreement DE-FC26-08NT05868 for the U.S. Department of Energy/National Energy Technology Laboratory (USDOE/NETL) entitled "Fuel Flexible Combustion Systems for High-Efficiency Utilization of Opportunity Fuels in Gas Turbines". The overall objective of this program was met with great success. GE was able to successfully demonstrate the operability of two fuel-flexible combustion nozzles over a wide range of opportunity fuels at heavy-duty gas turbine conditions while meeting emissions goals. The GE MS6000B ("6B") gas turbine engine was chosen as the target platform for new fuel-flexible premixer development. Comprehensive conceptual design and analysis of new fuel-flexible premixing nozzles were undertaken. Gas turbine cycle models and detailed flow network models of the combustor provide the premixer conditions (temperature, pressure, pressure drops, velocities, and air flow splits) and illustrate the impact of widely varying fuel flow rates on the combustor. Detailed chemical kinetic mechanisms were employed to compare some fundamental combustion characteristics of the target fuels, including flame speeds and lean blow-out behavior. Perfectly premixed combustion experiments were conducted to provide experimental combustion data of our target fuels at gas turbine conditions. Based on an initial assessment of premixer design requirements and challenges, the most promising sub-scale premixer concepts were evaluated both experimentally and computationally. After comprehensive screening tests, two best performing concepts were scaled up for further development. High pressure single nozzle tests were performed with the scaled premixer concepts at target gas turbine conditions with opportunity fuels. Single-digit NOx emissions were demonstrated for syngas fuels. Plasma-assisted pilot technology was demonstrated to enhance ignition capability and provide additional flame stability margin to a standard premixing fuel nozzle. However, the impact of plasma on NOx emissions was observed to be unacceptable given the goals of this program and difficult to avoid.

Venkatesan, Krishna

2011-11-30

12

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

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

13

Combustion gas properties. Part 3: Hydrogen gas fuel and dry air  

NASA Technical Reports Server (NTRS)

A series of computations has been made to produce the equilibrium temperature and gas composition for hydrogen gas fuel and dry air. The computed tables and figures provide combustion gas property data for pressures from 0.5 to 50 atmospheres and equivalence ratios from 0 to 2.0. Only sample tables and figures are provided in this report.

Wear, J. D.; Jones, R. E.; Mcbride, B. J.; Beyerle, R. A.

1985-01-01

14

Erosion combustion of a solid fuel for various gas flow temperatures  

Microsoft Academic Search

Several papers on the theory of erosion combustion indicate that turbulence in the flame zone increases the combustion rate of a solid fuel at high gas speeds. In the present paper, erosion combustion is considered for various incident temperatures and within two limiting cases: pressures of 2-8\\/MPa, where two zones of heat production in the combustion region allow the process

A. M. Lipanov; I. G. Rusyak

1983-01-01

15

Combustion of Coal-Gas Fuels in a Staged Combustor.  

National Technical Information Service (NTIS)

Gaseous fuels produced from coal resources have been considered for use in industrial gas turbines. Such fuels generally have heating values much lower than the typical gaseous fuel, natural gas; the low heating value could result in unstable or inefficie...

T. J. Rosfjord J. B. McVey R. A. Sederquist D. F. Schultz

1982-01-01

16

Erosion combustion of a solid fuel for various gas flow temperatures  

Microsoft Academic Search

Several papers in erosion combustion theory indicate that turbulence in the flame zone is responsible for increasing the combustion rate of a solid fuel at high gas speeds. This paper studies various incident temperatures in two limiting cases, low pressure p=2-8 MPa and pressures p (is greater than) 8 MPa. The systems of equations describing the steady state combustion of

A. M. Lipanov; I. G. Rusyaik

1983-01-01

17

Fuels research: Combustion effects overview  

NASA Technical Reports Server (NTRS)

The effects of broadened property fuels on gas turbine combustors were assessed. Those physical and chemical properties of fuels that affect aviation gas turbine combustion were isolated and identified. Combustion sensitivity to variations in particular fuel properties were determined. Advanced combustion concepts and subcomponents that could lessen the effect of using broadened property fuels were also identified.

Haggard, J. B., Jr.

1980-01-01

18

Premixed Combustion Models for Gas Turbine with Stratified Fueling Systems  

NASA Astrophysics Data System (ADS)

The most popular conventional combustion models are the “Eddy-Break-Up Model” by Spalding and “Eddy Dissipation Model” by Magnussen, both of which are accepted as applicable to premixed flames. However, these models have not simulated all the premixed combustion phenomena. In this paper we assess four combustion models; (1) “Eddy Dissipation Model”: “Magnussen Model” (2) premixed combustion model of the “Katsuki Model” which controls the reaction rate by the Damköhler number; (3) the “Kido Model”, which predicts turbulent burning velocity by laminar burning velocity and turbulent characteristics and (4) the “Modified Katsuki Model”, in which the fluctuations of concentrations and temperature are solved by the transport equation. In present work, the Kido model is newly presented as computational code based on the flame cell concept and the modified Katsuki model is also developed for application to multi-fuel systems. Our study showed that the “Modified Katsuki Model” could predict the premixed combustion phenomena sufficiently and could trace the changes of the frame front.

Mandai, Shigemi; Uda, Nobuki; Nishida, Hiroyuki

19

Proceedings of the 1999 international joint power generation conference (FACT-vol. 23). Volume 1: Fuels and combustion technologies; Gas turbines; and Nuclear engineering  

Microsoft Academic Search

Papers are arranged under the following topical sections: Gas turbine combustion; Advanced energy conversion; Low NOx solutions; Burner developments; Alternative fuels combustion; Advanced energy conversion technologies; Numerical modeling of combustion; Fluidized bed combustion; Coal combustion; Combustion research; Gasification systems; Mercury emissions; Highly preheated air combustion; Selective catalytic reduction; Special topics in combustion research; Gas turbines and advanced energy; and How

S. R. Jr. Penfield; N. A. Moussa

1999-01-01

20

Organic waste fuel combustion system integrated with a gas turbine combined cycle  

Microsoft Academic Search

This patent describes an apparatus. It is for integrating the firing and heat transfer components of a gas turbine combined steam generating plant with means for stabilizing combustion of high moisture content waste fuel, adapted to reheat the gas turbine exhaust gas intermediately within the combined cycle steam generating plant.

Strohmeyer; C. Jr

1990-01-01

21

Gasification of Indigenous Fuels. Part 4. Combustibility of Gas of Low Calorific Value.  

National Technical Information Service (NTIS)

Combustion equipment for gas of low calorific value has been constructed at the Laboratory of Fuel Processing and Lubrication Technology of the Technical Research Centre of Finland. A multifuel boiler of 25 kW is used for burning natural gas. The gas burn...

J. Leppaelahti E. Kurkela

1985-01-01

22

Proceedings of the 1998 international joint power generation conference (FACT-Vol.22). Volume 1: Fuels and combustion technologies; Gas turbines; Environmental engineering; Nuclear engineering  

Microsoft Academic Search

Papers are arranged under the following topical sections: Fuels and combustion technologies; Low NOx burner applications; Low cost solutions to utility NOx compliance issues; Coal combustion--Retrofit experiences, low NOx, and efficiency; Highly preheated air combustion; Combustion control and optimization; Advanced technology for gas fuel combustion; Spray combustion and mixing; Efficient power generation using gas turbines; Safety issues in power industry;

A. Gupta; R. Natole; A. Sanyal; J. Veilleux

1998-01-01

23

Combustion Gas Properties I-ASTM Jet a Fuel and Dry Air  

NASA Technical Reports Server (NTRS)

A series of computations was made to produce the equilibrium temperature and gas composition for ASTM jet A fuel and dry air. The computed tables and figures provide combustion gas property data for pressures from 0.5 to 50 atmospheres and equivalence ratios from 0 to 2.0.

Jones, R. E.; Trout, A. M.; Wear, J. D.; Mcbride, B. J.

1984-01-01

24

Pulsating combustion of gas fuel in the combustion chamber with closed resonant circuit  

NASA Astrophysics Data System (ADS)

In the combustion chambers of the pulsation of gas flow oscillation greatly accelerate heat dissipation to the walls of the combustion chamber and improve combustion efficiency as compared with a uniform combustion mode. This allows you to effectively solve a number of problems of industrial power, including an environmentally friendly combustion products. Significant drawback of such systems - the emitted noise exceeding the permissible requirements. One solution to this problem - the separation of the resonance tube into 2 parts connected at the output to the interference of sound waves. The results of theoretical studies pulsating combustion technical mixture of propane in the system, consisting of a combustion chamber and two resonance tubes forming a closed resonant circuit. Resonators have a variable length. Calculations have shown that under certain oscillation of the resonator length to the first resonant frequency of the system is achieved by reducing SPL more than 15 dB. For oscillations at a second resonant frequency is the complete elimination of noise while maintaining intense oscillations in the combustion chamber.

Yallina, E. V.; Larionov, V. M.; Iovleva, O. V.

2013-12-01

25

Combustion gas properties of various fuels of interest to gas turbine engineers  

NASA Technical Reports Server (NTRS)

A series of computations were made using the gas property computational schemes of Gordon and McBride to compute the gas properties and species concentration of ASTM-Jet A and dry air. The computed gas thermodynamic properties in a revised graphical format which gives information which is useful to combustion engineers is presented. A series of reports covering the properties of many fuel and air combinations will be published. The graphical presentation displays on one chart of the output of hundreds of computer sheets. The reports will contain microfiche cards, from which complete tables and graphs can be obtained. The extent of the planned effort and is documented samples of the many tables and charts that will be available on the microfiche cards are presented.

Jones, R. E.; Trout, A. M.; Wear, J. D.

1984-01-01

26

Corrosion monitoring using electrochemical noise and linear polarization resistance in fuel oil combustion gas environment  

Microsoft Academic Search

Corrosion monitoring of different steels is carried out online in a combustion rig firing 32 kg\\/h of fuel oil. Two temperature-controlled\\u000a probes are designed to allow control of the specimens temperature and the use of electrochemical noise (EN) and linear polarization\\u000a resistance (LPR) techniques for corrosion monitoring. Two probes are placed where the combustion gas reached a temperature\\u000a of 850–900°C,

V. M. Salinas-Bravo; J. Porcayo-Calderon; J. G. Gonzalez-Rodriguez

2006-01-01

27

Gas separation process using membranes with permeate sweep to remove CO.sub.2 from gaseous fuel combustion exhaust  

DOEpatents

A gas separation process for treating exhaust gases from the combustion of gaseous fuels, and gaseous fuel combustion processes including such gas separation. The invention involves routing a first portion of the exhaust stream to a carbon dioxide capture step, while simultaneously flowing a second portion of the exhaust gas stream across the feed side of a membrane, flowing a sweep gas stream, usually air, across the permeate side, then passing the permeate/sweep gas back to the combustor.

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

2012-05-15

28

Combined catalysts for the combustion of fuel in gas turbines  

DOEpatents

A catalytic oxidation module for a catalytic combustor of a gas turbine engine is provided. The catalytic oxidation module comprises a plurality of spaced apart catalytic elements for receiving a fuel-air mixture over a surface of the catalytic elements. The plurality of catalytic elements includes at least one primary catalytic element comprising a monometallic catalyst and secondary catalytic elements adjacent the primary catalytic element comprising a multi-component catalyst. Ignition of the monometallic catalyst of the primary catalytic element is effective to rapidly increase a temperature within the catalytic oxidation module to a degree sufficient to ignite the multi-component catalyst.

Anoshkina, Elvira V.; Laster, Walter R.

2012-11-13

29

Airfoil cooling hole plugging by combustion gas impurities of the type found in coal derived fuels  

NASA Technical Reports Server (NTRS)

The plugging of airfoil cooling holes by typical coal-derived fuel impurities was evaluated using doped combustion gases in an atmospheric pressure burner rig. Very high specific cooling air mass flow rates reduced or eliminated plugging. The amount of flow needed was a function of the composition of the deposit. It appears that plugging of film-cooled holes may be a problem for gas turbines burning coal-derived fuels.

Deadmore, D. L.; Lowell, C. E.

1979-01-01

30

Mild Combustion of Methane-Derived Fuel Mixtures: Natural Gas and Biogas  

Microsoft Academic Search

Mild combustion (also called diluted or flameless combustion) is an innovative combustion process able to strongly reduce pollutant emissions with respect to traditional combustion processes; it is characterized by high preheating of the combustion air and massive recycle of burned gases. While it is well known that mild combustion leads to lowering NOx emissions when pure fuels (such as methane)

Alessandro Effuggi; Davino Gelosa; Marco Derudi; Renato Rota

2008-01-01

31

Graphite fuels combustion off-gas treatment options.  

National Technical Information Service (NTIS)

Scenarios for burning bulk graphite and for burning crushed fuel particles from graphite spent nuclear fuels have been considered. Particulates can be removed with sintered metal filters. Subsequent cooling would then condense semi-volatile fission produc...

R. J. Kirkham R. E. Lords

1993-01-01

32

Comparison of combustion characteristics of ASTM A-1, propane, and natural-gas fuels in an annular turbojet combustor  

NASA Technical Reports Server (NTRS)

The performance of an annular turbojet combustor using natural-gas fuel is compared with that obtained using ASTM A-1 and propane fuels. Propane gas was used to simulate operation with vaporized kerosene fuels. The results obtained at severe operating conditions and altitude relight conditions show that natural gas is inferior to both ASTM A-1 and propane fuels. Combustion efficiencies were significantly lower and combustor pressures for relight were higher with natural-gas fuel than with the other fuels. The inferior performance of natural gas is shown to be caused by the chemical stability of the methane molecule.

Wear, J. D.; Jones, R. E.

1973-01-01

33

Application of neural network in the study of combustion rate of natural gas/diesel dual fuel engine.  

PubMed

In order to predict and improve the performance of natural gas/diesel dual fuel engine (DFE), a combustion rate model based on forward neural network was built to study the combustion process of the DFE. The effect of the operating parameters on combustion rate was also studied by means of this model. The study showed that the predicted results were good agreement with the experimental data. It was proved that the developed combustion rate model could be used to successfully predict and optimize the combustion process of dual fuel engine. PMID:12659230

Yan, Zhao-Da; Zhou, Chong-Guang; Su, Shi-Chuan; Liu, Zhen-Tao; Wang, Xi-Zhen

2003-01-01

34

Polycyclic aromatic hydrocarbon emissions from the combustion of alternative fuels in a gas turbine engine.  

PubMed

We report on the particulate-bound polycyclic aromatic hydrocarbons (PAH) in the exhaust of a test-bed gas turbine engine when powered by Jet A-1 aviation fuel and a number of alternative fuels: Sasol fully synthetic jet fuel (FSJF), Shell gas-to-liquid (GTL) kerosene, and Jet A-1/GTL 50:50 blended kerosene. The concentration of PAH compounds in the exhaust emissions vary greatly between fuels. Combustion of FSJF produces the greatest total concentration of PAH compounds while combustion of GTL produces the least. However, when PAHs in the exhaust sample are measured in terms of the regulatory marker compound benzo[a]pyrene, then all of the alternative fuels emit a lower concentration of PAH in comparison to Jet A-1. Emissions from the combustion of Jet A-1/GTL blended kerosene were found to have a disproportionately low concentration of PAHs and appear to inherit a greater proportion of the GTL emission characteristics than would be expected from volume fraction alone. The data imply the presence of a nonlinear relation between fuel blend composition and the emission of PAH compounds. For each of the fuels, the speciation of PAH compounds present in the exhaust emissions were found to be remarkably similar (R(2) = 0.94-0.62), and the results do provide evidence to support the premise that PAH speciation is to some extent indicative of the emission source. In contrast, no correlation was found between the PAH species present in the fuel with those subsequently emitted in the exhaust. The results strongly suggests that local air quality measured in terms of the particulate-bound PAH burden could be significantly improved by the use of GTL kerosene either blended with or in place of Jet A-1 kerosene. PMID:22534092

Christie, Simon; Raper, David; Lee, David S; Williams, Paul I; Rye, Lucas; Blakey, Simon; Wilson, Chris W; Lobo, Prem; Hagen, Donald; Whitefield, Philip D

2012-06-01

35

Experiments and modelling of natural gas combustion ignited by apilot diesel fuel spray  

Microsoft Academic Search

Experiments and numerical simulations have been carried out in order\\u000d\\u000a\\u0009to understand the combustion of natural gas (NG) under diesel cycle\\u000d\\u000a\\u0009conditions. The study used a natural gas\\/air mixture with a pilot\\u000d\\u000a\\u0009diesel fuel spray for ignition in a constant volume combustion chamber.\\u000d\\u000a\\u0009The experiments were carried out under conditions as close as possible\\u000d\\u000a\\u0009to those existing in a gas

Makame Mbarawa; Brain Edward Milton; Robert Thomas Casey

2001-01-01

36

Fuels, combustion, and lubrication  

SciTech Connect

This book contains the proceeding of this ASME in fuels, combustion, and lubrication. Topics covered include: combustion efficiency on residual fuels; marine diesel lubricants; uses and abuses; synthetic lubricants for high output medium-speed diesels.

Goyal, M.R. (John Deere Product Engineering Center (US))

1990-01-01

37

Graphite fuels combustion off-gas treatment options  

SciTech Connect

Scenarios for burning bulk graphite and for burning crushed fuel particles from graphite spent nuclear fuels have been considered. Particulates can be removed with sintered metal filters. Subsequent cooling would then condense semi-volatile fission products into or onto a particulate. These particulates would be trapped by a second sintered metal filter or downstream packed bed. A packed bed scrub column can be used to eliminate most of the iodine-129 and tritium. A molecular sieve bed is proposed to collect the residual {sup 129}I and other tramp radionuclides downstream (Ruthenium, etc.). Krypton-85 can be recovered, if need be, either by cryogenics or by the KALC process (Krypton Adsorption in Liquid Carbon dioxide). Likewise carbon-14 in the form of carbon dioxide could be collected with a caustic or lime scrub solution and incorporated into a grout. Sulfur dioxide present will be well below regulatory concern level of 4.0 tons per year and most of it would be removed by the scrubber. Carbon monoxide emissions will depend on the choice of burner and start-up conditions. Should the system exceed the regulatory concern level, a catalytic converter in the final packed bed will be provided. Radon and its daughters have sufficiently short half-lives (less than two minutes). If necessary, an additional holdup bed can be added before the final HEPA filters or additional volume can be added to the molecular sieve bed to limit radon emissions. The calculated total effective dose equivalent at the Idaho National Engineering Laboratory boundary from a single release of all the {sup 3}, {sup 14}C, {sup 85}Kr, and {sup 129}I in the total fuel mass if 0.43 mrem/year.

Kirkham, R.J.; Lords, R.E.

1993-03-01

38

Low NO sub x heavy fuel combustor concept program. Phase 1A: Combustion technology generation coal gas fuels  

NASA Technical Reports Server (NTRS)

Combustion tests of two scaled burners using actual coal gas from a 25 ton/day fluidized bed coal gasifier are described. The two combustor configurations studied were a ceramic lined, staged rich/lean burner and an integral, all metal multiannual swirl burner (MASB). The tests were conducted over a range of temperature and pressures representative of current industrial combustion turbine inlet conditions. Tests on the rich lean burner were conducted at three levels of product gas heating values: 104, 197 and 254 btu/scf. Corresponding levels of NOx emissions were 5, 20 and 70 ppmv. Nitrogen was added to the fuel in the form of ammonia, and conversion efficiencies of fuel nitrogen to NOx were on the order of 4 percent to 12 percent, which is somewhat lower than the 14 percent to 18 percent conversion efficiency when src-2 liquid fuel was used. The MASB was tested only on medium btu gas (220 to 270 btu/scf), and produced approximately 80 ppmv NOx at rated engine conditions. Both burners operated similarly on actual coal gas and erbs fuel, and all heating values tested can be successfully burned in current machines.

Sherlock, T. P.

1982-01-01

39

Single droplet combustion of coal slurry fuels  

Microsoft Academic Search

The combustion characteristics of single droplets of coal slurry fuels were experimentally investigated using both spontaneous and forced ignition. Results showed that the combustion is a sequential two-stage process, consisting of gas-phase combustion of the volatiles followed by combustion of the solid residue, which is mostly carbon. A splashing combustion phenomenon, which corresponds to the outgassing of the thermally cracked

T. Sakai; M. Saito

1983-01-01

40

Separation of particulate from flue gas of fossil fuel combustion and gasification  

DOEpatents

The gas from combustion or gasification of fossil fuel contains flyash and other particulate. The flyash is separated from the gas in a plurality of standleg moving granular-bed filter modules. Each module includes a dipleg through which the bed media flows into the standleg. The bed media forms a first filter bed having an upper mass having a first frusto-conical surface in a frusto-conical member at the entrance to the standleg and a lower mass having a second frusto-conical surface of substantially greater area than the first surface after it passes through the standleg. A second filter media bed may be formed above the first filter media bed. The gas is fed tangentially into the module above the first surface. The flyash is captured on the first frusto-conical surface and within the bed mass. The processed gas flows out through the second frusto-conical surface and then through the second filter bed, if present. The bed media is cleaned of the captured flyash and recirculated to the moving granular bed filter. Alternatively, the bed media may be composed of the ash from the combustion which is pelletized to form agglomerates. The ash flows through the bed only once; it is not recycled.

Yang, Wen-Ching (Murrysville, PA); Newby, Richard A. (Pittsburgh, PA); Lippert, Thomas E. (Murrysville, PA)

1997-01-01

41

Separation of particulate from flue gas of fossil fuel combustion and gasification  

DOEpatents

The gas from combustion or gasification of fossil fuel contains fly ash and other particulates. The fly ash is separated from the gas in a plurality of standleg moving granular-bed filter modules. Each module includes a dipleg through which the bed media flows into the standleg. The bed media forms a first filter bed having an upper mass having a first frusto-conical surface in a frusto-conical member at the entrance to the standleg and a lower mass having a second frusto-conical surface of substantially greater area than the first surface after it passes through the standleg. A second filter media bed may be formed above the first filter media bed. The gas is fed tangentially into the module above the first surface. The fly ash is captured on the first frusto-conical surface and within the bed mass. The processed gas flows out through the second frusto-conical surface and then through the second filter bed, if present. The bed media is cleaned of the captured fly ash and recirculated to the moving granular bed filter. Alternatively, the bed media may be composed of the ash from the combustion which is pelletized to form agglomerates. The ash flows through the bed only once; it is not recycled. 11 figs.

Yang, W.C.; Newby, R.A.; Lippert, T.E.

1997-08-05

42

Combustion performance of contaminated marine diesel fuels in a T63 gas-turbine combustor. Interim report, November 1983September 1985  

Microsoft Academic Search

The combustion performance of 26 fuel blends of Navy distillate fuel (NDF), heavy marine gas oil (HMGO), and a Jet A reference fuel contaminated with residuals containing various concentrations of asphaltenes, resins, and ash was measured in a T63 gas turbine combustor rig. Combustion-performance measurements included cold-start ignition, combustion efficiency, gaseous exhaust emissions, flame radiation, exhaust smoke, liner temperature, and

D. W. Naegeli; L. G. Dodge

1985-01-01

43

Effect of fuel gas composition in chemical-looping combustion with Ni-based oxygen carriers. 1. Fate of sulfur  

SciTech Connect

Chemical-looping combustion (CLC) has been suggested among the best alternatives to reduce the economic cost of CO{sub 2} capture using fuel gas because CO{sub 2} is inherently separated in the process. For gaseous fuels, natural gas, refinery gas, or syngas from coal gasification can be used. These fuels may contain different amounts of sulfur compounds, such as H{sub 2}S and COS. An experimental investigation of the fate of sulfur during CH{sub 4} combustion in a 500 W{sub th} CLC prototype using a Ni-based oxygen carrier has been carried out. The effect on the oxygen carrier behavior and combustion efficiency of several operating conditions such as temperature and H{sub 2}S concentration has been analyzed. Nickel sulfide, Ni3S{sub 2}, was formed at all operating conditions in the fuel reactor, which produced an oxygen carrier deactivation and lower combustion efficiencies. However, the oxygen carrier recovered their initial reactivity after certain time without sulfur addition. The sulfides were transported to the air reactor where SO{sub 2} was produced as final gas product. Agglomeration problems derived from the sulfides formation were never detected during continuous operation. Considering both operational and environmental aspects, fuels with sulfur contents below 100 vppm H{sub 2}S seem to be adequate to be used in an industrial CLC plant.

Garcia-Labiano, F.; de Diego, L.F.; Gayan, P.; Adanez, J.; Abad, A.; Dueso, C. [CSIC, Zaragoza (Spain)

2009-03-15

44

Gas Turbine Combustion and Emission Control.  

National Technical Information Service (NTIS)

The fundamentals of combustion are discussed in the context of gaseous and liquid fuels and gas turbine fuels. Methods for reducing the emission of pollutants in gas turbines are considered. These emissions are carbon monoxide, unburnt hydrocarbons, smoke...

B. Schetter

1993-01-01

45

Visualization of Gas-to-Liquid (GTL) Fuel Liquid Length and Soot Formation in the Constant Volume Combustion Chamber  

NASA Astrophysics Data System (ADS)

In this research, GTL spray combustion was visualized in an optically accessible quiescent constant-volume combustion chamber. The results were compared with the spray combustion of diesel fuel. Fast-speed photography with direct laser sheet illumination was used to determine the fuel liquid-phase length, and shadowgraph photography was used to determine the distribution of the sooting area in the fuel jet. The results showed that the fuel liquid-phase length of GTL fuel jets stabilized at about 20-22mm from the injector orifice and mainly depended on the ambient gas temperature and fuel volatility. GTL had a slightly shorter liquid length than that of the diesel fuel. This tendency was also maintained when multiple injection strategy was applied. The penetration of the tip of the liquid-phase fuel during pilot injection was a little shorter than the penetration during main injection. The liquid lengths during single and main injections were identical. In the case of soot formation, the results showed that soot formation was mainly affected by air-fuel mixing, and had very weak dependence on fuel volatility.

Azimov, Ulugbek; Kim, Ki-Seong

46

Modeling the effects of auxiliary gas injection and fuel injection rate shape on diesel engine combustion and emissions  

NASA Astrophysics Data System (ADS)

The effect of auxiliary gas injection and fuel injection rate-shaping on diesel engine combustion and emissions was studied using KIVA a multidimensional computational fluid dynamics code. Auxiliary gas injection (AGI) is the injection of a gas, in addition to the fuel injection, directly into the combustion chamber of a diesel engine. The objective of AGI is to influence the diesel combustion via mixing to reduce emissions of pollutants (soot and NO x). In this study, the accuracy of modeling high speed gas jets on very coarse computational grids was addressed. KIVA was found to inaccurately resolve the jet flows near walls. The cause of this inaccuracy was traced to the RNG k - ? turbulence model with the law-of-the-wall boundary condition used by KIVA. By prescribing the lengthscale near the nozzle exit, excellent agreement between computed and theoretical jet penetration was attained for a transient gas jet into a quiescent chamber at various operating conditions. The effect of AGI on diesel engine combustion and emissions was studied by incorporating the coarse grid gas jet model into a detailed multidimensional simulation of a Caterpillar 3401 heavy-duty diesel engine. The effects of AGI timing, composition, amount, orientation, and location were investigated. The effects of AGI and split fuel injection were also investigated. AGI was found to be effective at reducing soot emissions by increasing mixing within the combustion chamber. AGI of inert gas was found to be effective at reducing emissions of NOx by depressing the peak combustion temperatures. Finally, comparison of AGI simulations with experiments were conducted for a TACOM-LABECO engine. The results showed that AGI improved soot oxidation throughout the engine cycle. Simulation of fuel injection rate-shaping investigated the effects of three injection velocity profiles typical of unit-injector type, high-pressure common-rail type, and accumulator-type fuel injectors in the Caterpillar 3401 heavy-duty diesel engine. Pollutant emissions for the engine operating with different injection velocity profiles reflected the sensitivity of diesel engines to the location of pollutants within the combustion chamber, as influenced by the fuel injection.

Mather, Daniel Kelly

1998-11-01

47

Experimental study on combustion characteristics of a spark-ignition engine fueled with natural gas–hydrogen blends combining with EGR  

Microsoft Academic Search

An experimental study on the effect of hydrogen fraction and EGR rate on the combustion characteristics of a spark-ignition engine fueled with natural gas–hydrogen blends was investigated. The results show that flame development duration, rapid combustion duration and total combustion duration are increased with the increase of EGR rate and decreased with the increase of hydrogen fraction in the blends.

Erjiang Hu; Zuohua Huang; Bing Liu; Jianjun Zheng; Xiaolei Gu

2009-01-01

48

Integrated gas dynamic computational modelling and thermodynamic combustion diagnostics of multicylinder four-stroke spark ignition engine using compressed natural gas as a fuel  

Microsoft Academic Search

A comprehensive computational simulation model has been developed to describe the performance, efficiency and emission characteristics of the four-stroke multi-cylinder spark ignition engine which uses compressed natural gas as a fuel. This model performs an integrated simulation of thermodynamic, gas dynamic, and chemical kinetics of the whole engine system coupling with intake and exhaust manifolds. The thermodynamic combustion process is

J. V. Tirkey; H. N. Gupta; S. K. Shukla

2010-01-01

49

Fuel gas conditioning process  

DOEpatents

A process for conditioning natural gas containing C.sub.3+ hydrocarbons and/or acid gas, so that it can be used as combustion fuel to run gas-powered equipment, including compressors, in the gas field or the gas processing plant. Compared with prior art processes, the invention creates lesser quantities of low-pressure gas per unit volume of fuel gas produced. Optionally, the process can also produce an NGL product.

Lokhandwala, Kaaeid A. (Union City, CA)

2000-01-01

50

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

51

Effects of Combustion-Induced Vortex Breakdown on Flashback Limits of Syngas-Fueled Gas Turbine Combustors  

SciTech Connect

Turbine combustors of advanced power systems have goals to achieve very low pollutants emissions, fuel variability, and fuel flexibility. Future generation gas turbine combustors should tolerate fuel compositions ranging from natural gas to a broad range of syngas without sacrificing operational advantages and low emission characteristics. Additionally, current designs of advanced turbine combustors use various degrees of swirl and lean premixing for stabilizing flames and controlling high temperature NOx formation zones. However, issues of fuel variability and NOx control through premixing also bring a number of concerns, especially combustor flashback and flame blowout. Flashback is a combustion condition at which the flame propagates upstream against the gas stream into the burner tube. Flashback is a critical issue for premixed combustor designs, because it not only causes serious hardware damages but also increases pollutant emissions. In swirl stabilized lean premixed turbine combustors onset of flashback may occur due to (i) boundary layer flame propagation (critical velocity gradient), (ii) turbulent flame propagation in core flow, (iii) combustion instabilities, and (iv) upstream flame propagation induced by combustion induced vortex breakdown (CIVB). Flashback due to first two foregoing mechanisms is a topic of classical interest and has been studied extensively. Generally, analytical theories and experimental determinations of laminar and turbulent burning velocities model these mechanisms with sufficient precision for design usages. However, the swirling flow complicates the flashback processes in premixed combustions and the first two mechanisms inadequately describe the flashback propensity of most practical combustor designs. The presence of hydrogen in syngas significantly increases the potential for flashback. Due to high laminar burning velocity and low lean flammability limit, hydrogen tends to shift the combustor operating conditions towards flashback regime. Even a small amount of hydrogen in a fuel blend triggers the onset of flashback by altering the kinetics and thermophysical characteristics of the mixture. Additionally, the presence of hydrogen in the fuel mixture modifies the response of the flame to the global effects of stretch and preferential diffusion. Despite its immense importance in fuel flexible combustor design, little is known about the magnitude of fuel effects on CIVB induced flashback mechanism. Hence, this project investigates the effects of syngas compositions on flashback resulting from combustion induced vortex breakdown. The project uses controlled experiments and parametric modeling to understand the velocity field and flame interaction leading to CIVB driven flashback.

Ahsan Choudhuri

2011-03-31

52

An investigation of lean combustion in a natural gas-fueled spark-ignited engine  

Microsoft Academic Search

The objective of this work was to investigate the performance and emission characteristics of natural gas in an original equipment manufacturer (OEM), light-duty, spark-ignited engine being operated in the lean fueling regime and compare the operation with gasoline fueling cases. Data were acquired for several operating conditions of speed, throttle position, air-fuel equivalence ratio, and spark timing for both fuels.

M. Gupta; S. R. Bell; S. T. Tillman

1996-01-01

53

Task Report: Fuel Quality Assessment. Final Reort: Biomass Gasification Evaluation of Gas Turbine Combustion.  

National Technical Information Service (NTIS)

The scope of this study is to compare the compositions and characteristics of fuel gases prepared from biomass with those made by reforming natural gas, and to form a preliminary judgment about their suitability as engine fuels. Because the reforming proc...

2003-01-01

54

A study on low NOâ combustion in LBG-fueled 1500 C-class gas turbine  

Microsoft Academic Search

Developing integrated coal gasification combined-cycle systems ensures cost-effective and environmentally sound options for supplying future power generation needs. The reduction of NOâ emissions and increasing the inlet temperature of gas turbines are the most significant issues in gas turbine development in Integrated Coal Gasification Combined Cycle (IGCC) power generation systems. The coal gasified fuel, which is produced in a coal

T. Nakata; M. Sato; T. Ninomiya; T. Hasegawa

1996-01-01

55

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

56

Effect of fuel molecular structure on soot formation in gas turbine combustion  

NASA Technical Reports Server (NTRS)

The effect of fuel variations at the same hydrogen content on the formation of soot in a gas turbine combustor was studied. Six fuels were burned to a combustor over a matrix of about 50 test conditions with test conditions ranging over 500-1800 kPa (5-18 atm) pressure and 500-1000 K burner inlet temperature; fuel-air ratios were varied from 0.008-0.024. Flame radiation measurements were made through a sapphire window toward the end of the primary zone. The hydrogen content of the six test fuels ranged from 12.80 to 12.88%. Five fuels emphasized hydrocarbon types: (mono, di, and tricyclic), naphthenes (decalin) and partially hydrogenated aromatics (tetralin); the sixth fuel emphasized final boiling point.

Naegeli, D. W.; Moses, C. A.

1980-01-01

57

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

58

Flame combustion of carbonaceous fuels  

SciTech Connect

A method for improving the flame combustion of carbonaceous fuels. The method enables the reduction of oxides of nitrogen generated by the flame combustion, and enables an improvement in boiler efficiency. An ionic sodium or potassium compound, or a combination of them, is supplied with the combustible mixture of fuel and air so as intimately and uniformly to be present where and when the flame exists. Preferably the compound is supplied in an aqueous solution, and can be intimately mixed with the fuel, or with the atomizing air or steam, or with the combustion air. The process is useful with both single-stage and staged (multiple-staged) combustion systems.

Hampton, W.J.; Hatch, R.L.; James, G.R.

1984-05-08

59

Contribution of solid fuel, gas combustion or tobacco smoke to indoor air pollutant concentrations in Irish and Scottish homes  

PubMed Central

There are limited data describing pollutant levels inside homes that burn solid fuel within developed country settings with most studies describing test conditions or the effect of interventions. This study recruited homes in Ireland and Scotland where open combustion processes take place. Open combustion was classified as coal, peat or wood fuel burning, use of a gas cooker or stove, or where there is at least one resident smoker. 24-hour data on airborne concentrations of particulate matter less than 2.5 microns in size (PM2.5), carbon monoxide (CO), endotoxin in inhalable dust and carbon dioxide (CO2), together with 2–3 week averaged concentrations of nitrogen dioxide (NO2) were collected in 100 houses during the winter and spring of 2009–2010. The geometric mean of the 24-hour time-weighted-average (TWA) PM2.5 concentration was highest in homes with resident smokers (99?g/m3 – much higher than the WHO 24-hour guidance value of 25 ?g/m3. Lower geometric mean 24-hour TWA levels were found in homes that burned coal (7 ?g/m3) or wood (6 ?g/m3) and in homes with gas cookers (7 ?g/m3). In peat-burning homes the average 24-hourPM2.5 level recorded was 11 ?g/m3. Airborne endotoxin, CO, CO2 and NO2 concentrations were generally within indoor air quality guidance levels.

Semple, S; Garden, C; Coggins, M; Galea, KS; Whelan, P; Cowie, H; Sanchez-Jimenez, A; Thorne, PS; Hurley, JF; Ayres, JG

2012-01-01

60

Gas Turbine Combustion Chambers with Film Evaporation.  

National Technical Information Service (NTIS)

The paper reports on an attempt to apply Meurer's film vaporization combustion method (M-method), originally developed for diesel motors, to the combustion chambers of gas turbines. (In the M-method, instead of distributing the fuel in the air, it is laid...

A. W. Hussmann

1968-01-01

61

Combustion Characteristics and Performance of Low-Swirl Injectors with Natural Gas and Alternative Fuels At Elevated Pressures and Temperatures  

NASA Astrophysics Data System (ADS)

Stationary power-generating gas turbines in the United States have historically been fueled with natural gas, but due to its increasing price and the need to reduce carbon emissions, interest in alternative fuels is increasing. In order to effectively operate engines with these fuels their combustion characteristics need be well understood, especially at elevated pressures and temperatures. In this dissertation, the performance of blends of natural gas / methane with hydrogen and carbon dioxide, to simulate syngas and biogas, are evaluated in a model low-swirl stabilized combustor inside an optically accessible high-pressure vessel. The flashback and lean blow out limits, along with pollutant emissions, flow field, and turbulent displacement flame speeds, are measured as a function of fuel composition, pressure, inlet temperature, firing temperature, and flow rate in the range from 1 to 8 atm, 294 to 600K, 1350 to 1950K, and 20 to 60 m/s, respectively. These properties are quantified as a function of the inlet parameters. The lean blow-out limits are independent of pressure and inlet temperature but are weakly dependent on velocity. NOX emissions for both fuels were found to be exponentially dependent upon firing temperature, but emissions for the high-hydrogen flames were consistently higher than those of natural gas flames. The flashback limits for a 90%/10% (by volume) hydrogen/methane mixture increase with velocity and inlet temperature, but decrease with pressure. Correspondingly, the flame position progresses toward the combustor nozzle with increasing pressure and flame temperature, but away with increasing inlet temperature and velocity. Flashback occurred when the leading edge of the flame entered the nozzle. Local displacement turbulent flame speeds scale linearly with the turbulent fluctuating velocities, u', at the leading edge of the flame. Turbulent flame speeds for high-hydrogen fuels are twice that of natural gas for the same inlet conditions. The results from this study demonstrate the feasibility of using low-swirl combustors as a means to achieve robust, fuel flexible, and low emissions gas turbines in the future. The correlations and design guides developed with the data from this work will aid engineers by providing insight into the performance and optimization of low-swirl stabilized combustors.

Beerer, David Joseph

62

Thermodynamic and transport properties of air and its products of combustion with ASTMA-A-1 fuel and natural gas at 20, 30, and 40 atmospheres  

NASA Technical Reports Server (NTRS)

The isentropic exponent, molecular weight, viscosity, specific heat at constant pressure, thermal conductivity, Prandtl number, and enthalpy were calculated for air, the combustion products of ASTM-A-1 jet fuel and air, and the combustion products of natural gas and air. The properties were calculated over a temperature range from 300 to 2800 K in 100 K increments and for pressures of 20, 30 and 40 atmospheres. The data for natural gas and ASTM-A-1 were calculated for fuel-air ratios from zero to stoichiometric in 0.01 increments.

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

1973-01-01

63

Fuel Flexibility in Combustion  

SciTech Connect

This poster presents research findings from cofiring studies of various biomass feedstocks such as pentachlorophenol (PCP) and creosote-treated wood, lumber mill and furniture waste sawdusts, pallets, feedlot biomass (cattle manure), hybrid willow, and switchgrass with several bituminous and subbituminous coals. This research includes evaluation of advanced instrumentation and the study of interrelated combustion/emissions issues, such as char burnout, impacts on SO2, NOx, fine particulate (PM2.5), mercury (Hg) and other trace emissions, as well as issues impacting heat transfer, such as ash deposition slagging/fouling behavior. Biomass cofiring in large industrial and utility coal-fired boilers is a practical approach for increasing renewable energy given the wide availability, capital investment, and established performance of coal-fired boilers for providing efficient, low cost power. Although some utility biomass cofiring is successfully practiced in the U.S. and abroad, establishing long-term reliability and improving economics are still significant needs, along with research to support advanced combustion in future Vision 21 systems. Biomass cofiring in Vision 21 systems may reduce fossil CO2 emissions per MWe at capital and operations/maintenance cost savings relative to other technology options. Because an increasing number (currently 14) states have recently passed legislation establishing renewable portfolio standards (RPS), goals, or set-asides that will impact new power generation by 2009 and beyond, cofiring may broaden the appeal of Vision 21 systems to solve other environmental issues, including reducing landfill requirements. Legislation has been proposed to establish a federal RPS as well as extend IRS Section 29/45 tax credits (e.g., $0.005-0.010/kW-hr) for cofiring residues to supplement existing incentives, such as a $0.015/kW-hr tax credit for closed loop biomass (e.g., energy crops, such as switchgrass, hybrid willow) gasification. In addition, the coproduction/cogeneration concepts embodied in Vision 21 may also lend itself well to the type of utility/industry partnering involved in cofiring approaches. In light of the cost limitations in shipping distance (e.g., 50-100 miles or less) from collection to end-use based on the low energy density of biomass, resource availability is a site-specific consideration. Biomass fuels also exhibit significant differences in fuel characteristics, including volatility and ash chemistry that can also influence cofiring performance. Pilot-scale biomass cofiring tests have been conducted in the 150 kWt Combustion and Environmental Research Facility (CERF). A key aspect of the present work is to examine biomass char conversion for a range of initial particle sizes at various residence times for combustion relative to fuel processing/handling issues. In addition, a number of biomass cofiring R&D as well as full-scale utility demonstrations are providing technical insights to assist in cofiring technology commercialization. The paper will also discuss research plans, including lignin cofiring for ethanol/power co-production, novel concepts involving animal waste utilization, advanced combustion studies, and tri-firing concepts with other fuels.

Freeman, M.C.; O'Dowd, W.J.; Mathur, M.P. (U.S. DOE National Energy Technology Laboratory); Walbert, G.F. (Parsons Infrastructure and Technology, Inc.)

2001-11-06

64

Industrial Medium-Btu Fuel Gas Demonstration-Plant Program. Technical Support Report: Combustion System Data (Deliverable No. 46). Part 1. Comubstion Trials.  

National Technical Information Service (NTIS)

Combustion data for the Babcock and Wilcox (B and W) boiler spud burner were obtained as a part of the program to supply to potential users of Industrial Fuel Gas (IFG) the information necessary to make decisions regarding the suitability of their burners...

1979-01-01

65

A Study of Pollutant Formation from the Lean Premixed Combustion of Gaseous Fuel Alternatives to Natural Gas  

NASA Astrophysics Data System (ADS)

The goal of this research is to identify how nitrogen oxide (NO x) emissions and flame stability (blowout) are impacted by the use of fuels that are alternatives to typical pipeline natural gas. The research focuses on lean, premixed combustors that are typically used in state-of-the-art natural gas fueled systems. An idealized laboratory lean premixed combustor, specifically the jet-stirred reactor, is used for experimental data. A series of models, including those featuring detailed fluid dynamics and those focusing on detailed chemistry, are used to interpret the data and understand the underlying chemical kinetic reasons for differences in emissions between the various fuel blends. An ultimate goal is to use these data and interpretive tools to develop a way to predict the emission and stability impacts of changing fuels within practical combustors. All experimental results are obtained from a high intensity, single-jet stirred reactor (JSR). Five fuel categories are studied: (1) pure H 2, (2) process and refinery gas, including combinations of H2, CH4, C2H6, and C3H8, (3) oxygen blown gasified coal/petcoke composed of H2, CO, and CO2, (4) landfill and digester gas composed of CH4, CO2, and N2, and (5) liquified natural gas (LNG)/shale/associated gases composed of CH4, C2H6, and C3 H8. NOx measurements are taken at a nominal combustion temperature of 1800 K, atmospheric pressure, and a reactor residence time of 3 ms. This is done to focus the results on differences caused by fuel chemistry by comparing all fuels at a common temperature, pressure, and residence time. This is one of the few studies in the literature that attempts to remove these effects when studying fuels varying in composition. Additionally, the effects of changing temperature and residence time are investigated for selected fuels. At the nominal temperature and residence time, the experimental and modeling results show the following trends for NOx emissions as a function of fuel type: 1.) NOx emissions decrease with increasing H2 fuel fraction for combustion of CH4/H2 blends. This appears to be caused by a reduction in the amount of NO made by the prompt pathway involving the reaction of N2 with hydrocarbon radicals as the CH4 is replaced by H2. 2.) For category 2 (the process and refinery blend) and category 5 (the LNG, shale, and associated gases), NOx emissions increase with the addition of C2 and C3 hydrocarbons. This could be due to an increased production of free radicals resulting from increasing CO production when higher molecular weight hydrocarbons are broken down. 3.) For category 3 (the O2 blown gasified coal/petcoke), NOx emissions increase with increasing CO fuel fraction. The reason for this is attributed to CO producing more radicals per unit heat release than H2. When CO replaces H2, an increase in NOx emissions is seen due to an increase in the productivity of the N2O, NNH, and Zeldovich pathways. 4.) For category 4 (the landfill gas) the addition of diluents such as CO2 and N2 at constant air flow produces more NOx per kg of CH4 consumed, and N2 is more effective than CO 2 in increasing the NOx emission index. The increase in emission index appears to be due to an enhancement of the prompt NOx pathway as the diluents are added and the mixture moves towards stoichiometric. In addition, the presence of CO2 as a diluent catalyzes the loss of flame radicals, leading to less NOx formation than when an equivalent amount of N2 is used as a diluent. For a selected set of fuels, detailed spacial reactor probing is carried out. At the nominal temperature and residence time, the experimental results show the following trends for flame structure as a function of fuel type: 1.) Pure H2 is far more reactive in comparison to CH4 and all other pure alkane fuels. This results in relatively flat NO x and temperature profiles; whereas, the alkane fuels drop in both temperature and NOx production in the jet, where more fresh reactor feed gases are present. 2.) For category 2 (the Process and Refinery blends), H 2 addition increases reactivity in the

Fackler, Keith Boyd, Jr.

66

Combustion performance of contaminated marine diesel fuels in a T63 gas-turbine combustor. Interim report, November 1983-September 1985  

SciTech Connect

The combustion performance of 26 fuel blends of Navy distillate fuel (NDF), heavy marine gas oil (HMGO), and a Jet A reference fuel contaminated with residuals containing various concentrations of asphaltenes, resins, and ash was measured in a T63 gas turbine combustor rig. Combustion-performance measurements included cold-start ignition, combustion efficiency, gaseous exhaust emissions, flame radiation, exhaust smoke, liner temperature, and combustor can deposit formation. Except for ignition, these measurements were made at 4 operating conditions, 10% of full power (idle), 55, 75, and 100% of full power. Cold-start ignition measurements were made on 9 of the test fuels at burner inlet air temperatures ranging from 238K to 300K and fuel temperatures ranging from 263K to 300K. Droplet-size measurements were made of fuel sprays from the T63, LM2500, DDA 501-K17, and the TF40B atomizers using a Malvern light-scattering apparatus. These measurements were made on 7 fuels over a range of low fuel-flow rates comparable with those used for the ignition conditions of the respective engines. Correlation equations were developed relating Sauter mean-droplet diameter to fuel properties and flow conditions. The correlation equation developed for the T63 atomizer was used in a characteristic time-model calculation of the cold-start ignition data. Flame radiation and exhaust smoke correlated with hydrogen-carbon ratio. Fuels contaminated with residuals did not deviate significantly from the H/C ratio correlation. When neat NDF and HMGO were contaminated with residuals, there appeared to be a slight decrease in combustion efficiency and increase in total hydrocarbon and CO emissions.

Naegeli, D.W.; Dodge, L.G.

1985-12-01

67

Combustion engine for solid and liquid fuels  

NASA Technical Reports Server (NTRS)

A combustion engine having no piston, a single cylinder, and a dual-action, that is applicable for solid and liquid fuels and propellants, and that functions according to the principle of annealing point ignition is presented. The invention uses environmentally benign amounts of fuel and propellants to produce gas and steam pressure, and to use a simple assembly with the lowest possible consumption and constant readiness for mixing and burning. The advantage over conventional combustion engines lies in lower consumption of high quality igniting fluid in the most cost effective manner.

Pabst, W.

1986-01-01

68

Fine particle collection of an electrostatic precipitator in CO2-rich gas conditions for oxy-fuel combustion.  

PubMed

The collection of particles in CO(2)-enriched environments has long been important for the capture of CO(2) in order to clean gases via oxy-fuel combustion. We here report on the collection characteristics of fine and ultrafine particles using an electrostatic precipitator (ESP) in a CO(2)-enriched atmosphere. In order to understand the characteristics of particle collection in CO(2)-rich gas mixtures, the ionic properties of a CO(2)-enriched atmosphere was also investigated. The electrical mobility of the ions in a CO(2)-enriched atmosphere was found to be about 0.56 times that found in a conventional air atmosphere, due to the higher mass of CO(2) gas compared to that of air. The low electrical mobility of ions resulted in a low corona current under CO(2)-enriched conditions. The collection efficiency of particles in a CO(2)-rich atmosphere for a given power consumption was thus somewhat lower than that found in air, due to the low quantity of particle charging in CO(2)-enriched air. At the same time, higher temperatures led to the higher electrical mobility of ions, which resulted in a greater collection efficiency for a given power. The presence of a negative corona also led to a greater collection efficiency of particles in an ESP than that achieved for a positive corona. PMID:20692021

Han, Bangwoo; Kim, Hak Joon; Kim, Yong Jin

2010-10-01

69

BURNER DESIGN CRITERIA FOR NOX CONTROL FROM LOW-BTU GAS COMBUSTION: VOLUME II. ELEVATED FUEL TEMPERATURE  

EPA Science Inventory

The report gives results of a program to provide quantitative data on combustion emissions from high-temperature low-Btu gas. It complements a recently completed EPA project that evaluated emissions resulting from the burning of ambient-temperature low-Btu gas. The experimental r...

70

Combustion modeling in advanced gas turbine systems  

SciTech Connect

Goal of DOE`s Advanced Turbine Systems program is to develop and commercialize ultra-high efficiency, environmentally superior, cost competitive gas turbine systems for base-load applications in utility, independent power producer, and industrial markets. Primary objective of the program here is to develop a comprehensive combustion model for advanced gas turbine combustion systems using natural gas (coal gasification or biomass fuels). The efforts included code evaluation (PCGC-3), coherent anti-Stokes Raman spectroscopy, laser Doppler anemometry, and laser-induced fluorescence.

Smoot, L.D.; Hedman, P.O.; Fletcher, T.H.; Brewster, B.S.; Kramer, S.K. [Brigham Young Univ., Provo, UT (United States). Advanced Combustion Engineering Research Center

1995-12-31

71

ULTRA-DILUTE COMBUSTION OF PRIMARY REFERENCE FUELS  

Microsoft Academic Search

Using n-heptane and iso-octane as gasoline surrogate fuels, the laminar flame speeds, flame thicknesses, reaction zone thicknesses, and flammability limits of fuel\\/air\\/residual gas mixtures are computationally studied over ranges of pressures, temperatures, and dilution levels representative of unthrottled HCCI operation. These calculations are further used to characterize the combustion regime for spark-initiated HCCI combustion. In a turbulent premixed combustion regime

YIMIN HUANG; CHIH-JEN SUNG; KAMAL KUMAR

2007-01-01

72

Method for in-flight combustion of carbonaceous fuels  

Microsoft Academic Search

An apparatus and method for combusting carbonaceous fuels includes a reaction chamber defining a reaction zone and means for injecting fuel and oxidizer gas in a manner to produce in the reaction zone a wheel-type flow of the fuel-gas mixture. In preferred embodiments, the high velocity wheel-type flow operates to suspend fuel or other reactant particles in the swirling gas

H. L. Burge; J. A. Hardgrove; W. F. Krieve

1980-01-01

73

Life cycle assessment of fuels for district heating: A comparison of waste incineration, biomass- and natural gas combustion  

Microsoft Academic Search

The aim of this consequential life cycle assessment (LCA) is to compare district heating based on waste incineration with combustion of biomass or natural gas. The study comprises two options for energy recovery (combined heat and power (CHP) or heat only), two alternatives for external, marginal electricity generation (fossil lean or intense), and two alternatives for the alternative waste management

Ola Eriksson; Göran Finnveden; Tomas Ekvall; Anna Björklund

2007-01-01

74

Burner Design Criteria for NOx Control from Low-BTU Gas Combustion: Volume II. Elevated Fuel Temperature.  

National Technical Information Service (NTIS)

The report gives results of a program to provide quantitative data on combustion emissions from high-temperature low-Btu gas. It complements a recently completed EPA project that evaluated emissions resulting from the burning of ambient-temperature low-Bt...

D. R. Shoffstall R. T. Waibel

1977-01-01

75

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) [Lacon, IL

2007-10-09

76

Fluidized-bed combustion fuel  

Microsoft Academic Search

This patent describes a process for producing from a solid carbonaceous refuse a high ash fuel for use in a circulating fluidized-bed combustion chamber. It comprises separating from the refuse a carbonaceous portion having an ash content in a selected range percent by weight; separating the carbonaceous portion into first and second fractions, the first fraction being at or above

Rich; J. W. Jr

1990-01-01

77

Combustion oscillation control by cyclic fuel injection  

SciTech Connect

A number of recent articles have demonstrated the use of active control to mitigate the effects of combustion instability in afterburner and dump combustor applications. In these applications, cyclic injection of small quantities of control fuel has been proposed to counteract the periodic heat release that contributes to undesired pressure oscillations. This same technique may also be useful to mitigate oscillations in gas turbine combustors, especially in test rig combustors characterized by acoustic modes that do not exist in the final engine configuration. To address this issue, the present paper reports on active control of a subscale, atmospheric pressure nozzle/combustor arrangement. The fuel is natural gas. Cyclic injection of 14% control fuel in a premix fuel nozzle is shown to reduce oscillating pressure amplitude by a factor of 0.30 (i.e., {approximately}10 dB) at 300 Hz. Measurement of the oscillating heat release is also reported.

Richards, G.A.; Yip, M.J. [USDOE Morgantown Energy Technology Center, WV (United States); Robey, E. [EG& G Technical Services of West Virginia, Morgantown Energy Technology Center, WV (United States); Cowell, L.; Rawlins, D. [Solar Turbines, Inc., San Diedgo, CA (United States)

1995-04-01

78

SSSStudy on Combustion Characteristics of the Blast Furnace Gas in the Constant Volume Combustion Bomb  

Microsoft Academic Search

Blast furnace gas is the byproduct of smelting steel production process, and is the important secondary energy source. It is can be used as fuel for engines to generate electricity for most middle and small steel enterprises. In order to understand the combustion mechanism and provide the basis for the design of blast furnace gas engine,premixed laminar combustion experiments of

LIU YONGQI; WANG HAIFENG; LI PING

79

Combustion-Gas Sampling System.  

National Technical Information Service (NTIS)

A molecular beam gas sampling apparatus was designed and fabricated to extract combustion gases from high pressure, high temperature environments. The device is intended to transfer the gases with minimal change to a detector such as a mass spectrometer. ...

J. Kahrs

1970-01-01

80

Method of combustion for dual fuel engine  

DOEpatents

Apparatus and a method of introducing a primary fuel, which may be a coal water slurry, and a high combustion auxiliary fuel, which may be a conventional diesel oil, into an internal combustion diesel engine comprises detecting the load conditions of the engine, determining the amount of time prior to the top dead center position of the piston to inject the main fuel into the combustion chamber, and determining the relationship of the timing of the injection of the auxiliary fuel into the combustion chamber to achieve a predetermined specific fuel consumption, a predetermined combustion efficiency, and a predetermined peak cylinder firing pressure. 19 figures.

Hsu, B.D.; Confer, G.L.; Zujing Shen; Hapeman, M.J.; Flynn, P.L.

1993-12-21

81

Method of combustion for dual fuel engine  

DOEpatents

Apparatus and a method of introducing a primary fuel, which may be a coal water slutty, and a high combustion auxiliary fuel, which may be a conventional diesel oil, into an internal combustion diesel engine comprises detecting the load conditions of the engine, determining the amount of time prior to the top dead center position of the piston to inject the main fuel into the combustion chamber, and determining the relationship of the timing of the injection of the auxiliary fuel into the combustion chamber to achieve a predetermined specific fuel consumption, a predetermined combustion efficiency, and a predetermined peak cylinder firing pressure.

Hsu, Bertrand D. (Erie, PA); Confer, Gregory L. (Erie, PA); Shen, Zujing (Erie, PA); Hapeman, Martin J. (Edinboro, PA); Flynn, Paul L. (Fairview, PA)

1993-12-21

82

Industrial gas turbine combustion performance test of DME to use as an alternative fuel for power generation  

Microsoft Academic Search

DME (dimethyl ether, CH3OCH3) is both a good alternative fuel for transportation and power generation and an LPG substitute owing to its cleanliness, multi-source productivity and the ease with which it is transported. This study was conducted to verify whether DME is a good fuel for gas turbines and to identify potential problems in fuelling a commercial gas turbine with

Min Chul Lee; Seok Bin Seo; Jae Hwa Chung; Yong Jin Joo; Dal Hong Ahn

2009-01-01

83

FUEL RICH SULFUR CAPTURE IN A COMBUSTION ENVIRONMENT  

EPA Science Inventory

A refractory-lined, natural gas furnace was used to study fuel rich sulfur capture reactions of calcium sorbents under typical combustion conditions. The fuel rich sulfur species H2S and COS were monitored in a near-continuous fashion using a gas chromatograph equipped with a fl...

84

Combustor nozzle for a fuel-flexible combustion system  

DOEpatents

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

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

2011-03-22

85

Varying area fuel system for combustion engine  

Microsoft Academic Search

The patent describes a fuel injection apparatus for a spark ignition internal combustion engine having at least one cylinder and an air inlet, and injection nozzle for injecting fuel into the cylinder, a fuel feed line for supplying fuel under pressure to the injection nozzle, the fuel feed line being one leg of a return fuel circuit. The fuel circuit

1988-01-01

86

Gas turbine combustion instability.  

National Technical Information Service (NTIS)

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 ...

G. A. Richards G. T. Lee

1996-01-01

87

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

88

Removal of SOx, NOx, and particulate from combusted carbonaceous fuels  

Microsoft Academic Search

The invention is a method for removing sulfur oxides, nitrogen oxides and particulate from the products of combusted carbonaceous fuels. Sulfur oxides, nitrogen oxides and particulate are currently discharged to the atmosphere as flue gas in quantities highly detrimental to the environment. Potassium compounds, as are found in agricultural grade potash, are dispersed throughout the combustion products at the exit

Dayen

1985-01-01

89

Fuel and Additive Characterization for HCCI Combustion.  

National Technical Information Service (NTIS)

This paper shows a numerical evaluation of fuels and additives for HCCl combustion. First, a long list of candidate HCCl fuels is selected. For all the fuels in the list, operating conditions (compression ratio, equivalence ratio and intake temperature) a...

S. M. Aceves D. Flowers J. Martinez-Frias F. Espinosa-Lopez W. J. Pitz R. Dibble

2003-01-01

90

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

91

Variability in natural gas fuel composition and its effects on the performance of catalytic combustion systems. Final report for period September 18, 1998 - September 17, 2000  

SciTech Connect

Natural gas is composed primarily of methane with small amounts of higher hydrocarbons and diluents, which vary by region and over time. Compositions of natural gas from domestic and worldwide sources were surveyed with respect to content of higher hydrocarbons and diluents. The survey showed slight compositional variability between most of the gases, with a small fraction of them containing significantly larger contents of higher hydrocarbons than the mean. As gas-fired turbines will be used for power generation all over the world, they will need to tolerate operation with fuels with a wide variety of compositions, particularly with respect to the concentration of higher hydrocarbons and diluents. Subscale catalytic combustion modules typical of those used in gas turbine power generation with ultra low emissions of pollutants were tested in a subscale test system with natural gas alone and with added known levels of hydrocarbon compounds and diluents. The range of compositions tested contained the range observed in the survey. Test results were used to calculate the effect of composition on catalyst performance. The compositional variability is of little consequence to the catalyst for most of the gases in the survey, including nearly all of the gases delivered in the U.S. To accommodate the remaining gases, the catalyst inlet temperature must be lowered to maintain combustor durability. These results support commercial acceptance of catalytic combustion systems for use in natural gas fired turbines in distributed power generation with ultra low NO{sub x} emissions.

Ginter, David; Simchick, Chuck; Schlatter, Jim

2002-03-01

92

Integrated process for gasifying and combusting a carbonaceous fuel  

Microsoft Academic Search

An integrated gasification\\/combustion process is described for sulfur and nitrogen-bearing carbonaceous fuels wherein a flue gas is produced having a reduced content of sulfur-based and nitrogen-based compounds. The process consists of: a. gasifying a first portion of the carbonaceous fuel in a gasification reactor in the presence of air to produce a hot char-containing carbon monoxide-rich fuel gas having a

Tanca

1986-01-01

93

Study on the combustion characteristics of low calorific value gas in the Constant Volume Combustion Bomb  

Microsoft Academic Search

A Constant Volume Combustion system is introduced in this paper, which was used to investigate the combustion characteristics of gaseous fuel. In the system, the combination of methane and Carbon dioxide was conducted to simulate the low calorific value gas-biogas. The purpose of the experimental research which was performed on the system is to study the effects of the fraction

Xuejiao Han; Hongguang Zhang; Xiaolei Bai

2011-01-01

94

Oxy-fuel combustion with integrated pollution control  

DOEpatents

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

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

2012-01-03

95

A Nonlinear Model for Fuel Atomization in Spray Combustion  

NASA Technical Reports Server (NTRS)

Most gas turbine combustion codes rely on ad-hoc statistical assumptions regarding the outcome of fuel atomization processes. The modeling effort proposed in this project is aimed at developing a realistic model to produce accurate predictions of fuel atomization parameters. The model involves application of the nonlinear stability theory to analyze the instability and subsequent disintegration of the liquid fuel sheet that is produced by fuel injection nozzles in gas turbine combustors. The fuel sheet is atomized into a multiplicity of small drops of large surface area to volume ratio to enhance the evaporation rate and combustion performance. The proposed model will effect predictions of fuel sheet atomization parameters such as drop size, velocity, and orientation as well as sheet penetration depth, breakup time and thickness. These parameters are essential for combustion simulation codes to perform a controlled and optimized design of gas turbine fuel injectors. Optimizing fuel injection processes is crucial to improving combustion efficiency and hence reducing fuel consumption and pollutants emissions.

Liu, Nan-Suey (Technical Monitor); Ibrahim, Essam A.; Sree, Dave

2003-01-01

96

Gas Turbine Combustion Modeling.  

National Technical Information Service (NTIS)

To effectively use multidimensional models for gas tubine combustor design and development activities, a method is presented to compute aerothermal performance parameters including CO, unburned hydrocarbon, NOx and smoke emissions; lean blowout and igniti...

H. C. Mongia

1988-01-01

97

Fuel injection system for internal combustion engine  

Microsoft Academic Search

This patent describes a fuel injection system for an internal combustion engine provided with an intake passage, a cylinder associated with the intake passage and at least one intake valve associated with the cylinder, the fuel injection system including a fuel injector adapted to be disposed upstream of the intake valve. The fuel injector consists of: a housing, a hollow

H. Kiuchi; O. Ogawa; H. Yamazoe; H. Tasaka; M. Kuroda; S. Okino

1988-01-01

98

Fluidized-bed combustion fuel  

SciTech Connect

This patent describes a process for producing from a solid carbonaceous refuse a high ash fuel for use in a circulating fluidized-bed combustion chamber. It comprises separating from the refuse a carbonaceous portion having an ash content in a selected range percent by weight; separating the carbonaceous portion into first and second fractions, the first fraction being at or above a selected size; crushing the first fraction; and combining the crushed first fraction with the second fraction. Also described is a process wherein the selected ash content range is between about 30 percent and about 50 percent, by weight. Also described is a process wherein the selected size is above about 1/4 inch.

Rich, J.W. Jr.

1990-10-09

99

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

100

Fundamentals of Gas Turbine combustion  

NASA Technical Reports Server (NTRS)

Combustion problems and research recommendations are discussed in the areas of atomization and vaporization, combustion chemistry, combustion dynamics, and combustion modelling. The recommendations considered of highest priority in these areas are presented.

Gerstein, M.

1979-01-01

101

Combustion and fuel characterization of coal-water fuels  

SciTech Connect

This five-year research project was established to provide sufficient data on coal-water fuel (CWF) chemical, physical, and combustion properties to assess the potential for commercial firing in furnaces designed for gas or oil firing. Extensive laboratory testing was performed at bench-scale, pilot-scale (4 {times} 10{sup 6}Btu/hr) and commercial-scale (25 {times} 10{sup 6} to 50 {times} 10{sup 6}Btu/hr) on a cross-section of CWFs. Fuel performance characteristics were assessed with respect to coal properties, level of coal beneficiation, and slurry formulation. The performance of four generic burner designs was also assessed. Boiler performance design models were applied to analyze the impacts associated with conversion of seven different generic unit designs to CWF firing. Equipment modifications, operating limitations, and retrofit costs were determined for each design when utilizing several CWFs. This report summarizes studies conducted under Task 4. The objective was to quantify CWF atomization and combustion properties utilizing industrial/utility scale equipment. Burners were evaluated and combustion performance differences identified for various CWF formulations. 12 refs., 23 figs., 6 tabs.

Lachowicz, Y.V.; LaFlesh, R.C.

1987-07-01

102

Combustion behavior of solid fuel ramjets  

NASA Technical Reports Server (NTRS)

Nonreacting flowfield characteristics and fundamental fuel properties are considered with respect to their use in estimating the obtainable combustion efficiency for fuels and/or combustor geometries. It is shown that near wall turbulence intensity in nonreacting flow appears to correlate reasonably well with the fuel regression pattern in identical geometries. The HTPB based fuels exhibit solid phase exothermic reactions in contrast to purely endothermic reactions for plexiglas. It is further shown that combustion pressure oscillations appear to be related to physically induced disturbances to the fluctuating shear layers at the fuel grain and aft mixing chamber inlets.

Netzer, D. W.; Binn, B. A.; Scott, W. E.; Metochianakis, M.

1980-01-01

103

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

104

Effects of ambient conditions and fuel composition on combustion stability  

SciTech Connect

Recent regulations on NO, emissions are promoting the use of lean premix (LPM) combustion for industrial gas turbines. LPM combustors avoid locally stoichiometric combustion by premixing fuel and the air upstream of the reaction region, thereby eliminating the high temperatures that produce thermal NO.. Unfortunately, this style of combustor is prone to combustion oscillation. Significant pressure fluctuations can occur when variations in heat release periodically couple pressure to acoustic modes in the combustion chamber. These oscillations must be controlled because resulting vibration can shorten the life of engine hardware. Laboratory and engine field testing have shown that instability regimes can vary with environmental conditions. These observations prompted this study of the effects of ambient conditions and fuel composition on combustion stability. Tests are conducted on a sub-scale combustor burning natural gas, propane, and some hydrogen/hydrocarbon mixtures. A premix, swirl-stabilized fuel nozzle typical of industrial gas turbines is used. Experimental and numerical results describe how stability regions may shift as inlet air temperature, humidity, and fuel composition are altered. Results appear to indicate that shifting instability instability regimes are primarily caused by changes in reaction rate.

Janus, M.C.; Richards, G.A.; Yip, M.J. [USDOE Federal Energy Technology Center, Morgantown, WV (United States); Robey, E.H. [EG& G Technical Services of West Virginia (United States)

1997-04-01

105

Flashback Detection Sensor for Hydrogen Augmented Natural Gas Combustion  

SciTech Connect

The use of hydrogen augmented fuel is being investigated by various researchers as a method to extend the lean operating limit, and potentially reduce thermal NOx formation in natural gas fired lean premixed (LPM) combustion systems. The resulting increase in flame speed during hydrogen augmentation, however, increases the propensity for flashback in LPM systems. Real-time in-situ monitoring of flashback is important for the development of control strategies for use of hydrogen augmented fuel in state-of-the-art combustion systems, and for the development of advanced hydrogen combustion systems. The National Energy Technology Laboratory (NETL) and Woodward Industrial Controls are developing a combustion control and diagnostics sensor (CCADS), which has already been demonstrated as a useful sensor for in-situ monitoring of natural gas combustion, including detection of important combustion events such as flashback and lean blowoff. Since CCADS is a flame ionization sensor technique, the low ion concentration produced in pure hydrogen combustion raises concerns of whether CCADS can be used to monitor flashback in hydrogen augmented combustion. This paper discusses CCADS tests conducted at 0.2-0.6 MPa (2-6 atm), demonstrating flashback detection with fuel compositions up to 80% hydrogen (by volume) mixed with natural gas. NETL’s Simulation Validation (SimVal) combustor offers full optical access to pressurized combustion during these tests. The CCADS data and high-speed video show the reaction zone moves upstream into the nozzle as the hydrogen fuel concentration increases, as is expected with the increased flame speed of the mixture. The CCADS data and video also demonstrate the opportunity for using CCADS to provide the necessary in-situ monitor to control flashback and lean blowoff in hydrogen augmented combustion applications.

Thornton, J.D.; Chorpening, B.T.; Sidwell, T.; Strakey, P.A.; Huckaby, E.D.; Benson, K.J. (Woodward)

2007-05-01

106

Engine combustion control via fuel reactivity stratification  

DOEpatents

A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choose the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

Reitz, Rolf Deneys; Hanson, Reed M; Splitter, Derek A; Kokjohn, Sage L

2013-12-31

107

Fuel control apparatus in internal combustion engine  

SciTech Connect

A fuel control apparatus is an internal combustion engine arranged to increase a quantity of fuel supply uniquely determined on the basis of an engine speed and a quantity of suction air by a predetermined quantity upon detection of acceleration of the internal combustion engine is described comprising: a detection means for detecting acceleration and deceleration of the internal combustion engine; an engine speed operation means for calculating the number of engine resolutions; a calculation means for calculating a continuous acceleration correcting factor representing a quantity to be subtracted from the predetermined quantity in accordance with the value of integration of the number of engine revolutions calculated by the engine speed operation means; and a fuel supply means for supplying fuel to the internal combustion engine in accordance with an output of the calculation means.

Morita, K.; Miyake, J.; Hatanaka, K.; Sakuma, K.

1988-05-17

108

40 CFR 60.107a - Monitoring of emissions and operations for fuel gas combustion devices and flares.  

Code of Federal Regulations, 2013 CFR

...flow rate, fuel oil flow rate (as applicable) and heating value content according...section; and for fuel oil streams, determine the heating value according to...flow rate, fuel oil flow rate (as applicable) and heating value content...

2013-07-01

109

Energy Content in Flue Gases from Combustion of Fossil Fuels.  

National Technical Information Service (NTIS)

The enthalpy and average specific heat of flue gas from the combustion of fossil fuels of known composition have been calculated as a function of temperature and presented in diagrams. Specific heat data at constant pressure as a function of temperature f...

B. Solbracke

1975-01-01

110

Conceptual design of the cooling system for 1700 C-class, hydrogen-fueled combustion gas turbines  

SciTech Connect

The effects of three types of cooling systems on the calculated operating performances of a hydrogen-fueled thermal power plant with a 1,700 C-class gas turbine were studied with the goal of attaining a thermal efficiency of greater than 60%. The combination of a closed-circuit water cooling system for the nozzle blades and a steam cooling system for the rotor blades was found to be the most efficient, since it eliminated the penalties of a conventional open-circuit cooling system which ejects coolant into the main hot gas stream. Based on the results, the water cooled, first-stage nozzle blade and the steam cooled first-stage rotor blade were designed. The former features array of circular cooling holes close to the surface and uses a copper alloy taking advantage of recent coating technologies such as thermal barrier coatings (TBCs) and metal coatings to decrease the temperature and protect the blade core material. The later has cooling by serpentine cooling passages with V-shaped staggered turbulence promoter ribs which intensify the internal cooling.

Kizuka, N.; Sagae, K.; Anzai, S.; Marushima, S.; Ikeguchi, T.; Kawaike, K. [Hitachi Ltd., Hitachinaki, Ibaraki (Japan)

1999-01-01

111

Characteristics and combustion of future hydrocarbon fuels  

NASA Technical Reports Server (NTRS)

Changes in fuel properties that are expected in future hydrocarbon fuels for aircraft are discussed along with the principal properties of 'syncrudes' and the fuels that can be derived from them. The impact that the resultant potential changes in fuel properties may have on combustion and thermal stability characteristics is illustrated and discussed in terms of ignition, soot formation, carbon deposition, flame radiation, and emissions.

Rudey, R. A.; Grobman, J. S.

1978-01-01

112

Combustion-assisted plasma in fuel conversion  

NASA Astrophysics Data System (ADS)

The long history of plasma application for fuel conversion shows that reasonably low specific energy requirement has been achieved in most cases using non-equilibrium systems with relatively high local temperature ('warm' plasmas). Analysis of reasons for this trend presented in this paper indicates that transitional warm plasma discharge systems are optimal for large-scale fuel processing. This analysis also reveals one specific feature of warm discharges that was not discussed earlier: warm discharge-based plasma-chemical systems are very sensitive to gas temperature and chemical reactions. When temperature reaches the level that is high enough to support chemical reactions in a particular system (ignition temperature), chemical reactions produce high concentration of excited molecules, and these molecules form a basis for stepwise ionization. This results in a significant drop in the energy necessary to support electric discharge in the system for two reasons. First, stepwise ionization that requires relatively low electron energy overcomes direct ionization that is typical for low-temperature non-equilibrium plasmas and requires much higher ionization energy. Second, high temperature of surrounding gas reduces heat losses from the discharge channel, while a significant portion of the discharge energy in warm plasma systems should be spent to compensate these losses. Thus, an intensive chemical reaction, e.g. combustion, supports the existence of a warm electric discharge.

Gutsol, A.; Rabinovich, A.; Fridman, A.

2011-07-01

113

Combustion Sensors: Gas Turbine Applications  

NASA Technical Reports Server (NTRS)

This report documents efforts to survey the current research directions in sensor technology for gas turbine systems. The work is driven by the current and future requirements on system performance and optimization. Accurate real time measurements of velocities, pressure, temperatures, and species concentrations will be required for objectives such as combustion instability attenuation, pollutant reduction, engine health management, exhaust profile control via active control, etc. Changing combustor conditions - engine aging, flow path slagging, or rapid maneuvering - will require adaptive responses; the effectiveness of such will be only as good as the dynamic information available for processing. All of these issues point toward the importance of continued sensor development. For adequate control of the combustion process, sensor data must include information about the above mentioned quantities along with equivalence ratios and radical concentrations, and also include both temporal and spatial velocity resolution. Ultimately these devices must transfer from the laboratory to field installations, and thus must become low weight and cost, reliable and maintainable. A primary conclusion from this study is that the optics-based sensor science will be the primary diagnostic in future gas turbine technologies.

Human, Mel

2002-01-01

114

Fireside Corrosion in Oxy-Fuel Combustion of Coal  

SciTech Connect

Oxy-fuel combustion is based on burning fossil fuels in a mixture of recirculated flue gas and oxygen, rather than in air. An optimized oxy-combustion power plant will have ultra-low emissions since the flue gas that results from oxy-fuel combustion consists almost entirely of CO2 and water vapor. Once the water vapor is condensed, it is relatively easy to sequester the CO2 so that it does not escape into the atmosphere. A variety of laboratory tests comparing air-firing to oxy-firing conditions, and tests examining specific simpler combinations of oxidants, were conducted at 650-700 C. Alloys studied included model Fe-Cr and Ni-Cr alloys, commercial ferritic steels, austenitic steels, and nickel base superalloys. The observed corrosion behavior shows accelerated corrosion even with sulfate additions that remain solid at the tested temperatures, encapsulation of ash components in outer iron oxide scales, and a differentiation between oxy-fuel combustion flue gas recirculation choices.

Holcomb, Gordon R.; Tylczak, Joseph; Meier, G.H.; Jung. K.; Mu, N.; Yanar, N.M.; Pettit, F.S.

2012-08-01

115

Gas turbine containing an additional combustion gas compressor  

Microsoft Academic Search

A gas turbine containing an additional combustion gas compressor and a gearing drive which, on the one hand, is rotatably connected by means of a rigid coupling and an axial bearing with the gas turbine and, on the other hand, is rotatably connected by means of a further rigid coupling with the combustion gas compressor. Furthermore, the gearing drive serves

Zaba

1983-01-01

116

Fuel and Additive Characterization for HCCI Combustion  

SciTech Connect

This paper shows a numerical evaluation of fuels and additives for HCCl combustion. First, a long list of candidate HCCl fuels is selected. For all the fuels in the list, operating conditions (compression ratio, equivalence ratio and intake temperature) are determined that result in optimum performance under typical operation for a heavy-duty engine. Fuels are also characterized by presenting Log(p)-Log(T) maps for multiple fuels under HCCl conditions. Log(p)-Log(T) maps illustrate important processes during HCCl engine operation, including compression, low temperature heat release and ignition. Log(p)-Log(T) diagrams can be used for visualizing these processes and can be used as a tool for detailed analysis of HCCl combustion. The paper also includes a ranking of many potential additives. Experiments and analyses have indicated that small amounts (a few parts per million) of secondary fuels (additives) may considerably affect HCCl combustion and may play a significant role in controlling HCCl combustion. Additives are ranked according to their capability to advance HCCl ignition. The best additives are listed and an explanation of their effect on HCCl combustion is included.

Aceves, S M; Flowers, D; Martinez-Frias, J; Espinosa-Loza, F; Pitz, W J; Dibble, R

2003-02-12

117

Combustion Studies of Coal Derived Fuels.  

National Technical Information Service (NTIS)

Combustion studies were conducted to evaluate the suitability of using a coal-derived aviation fuel as a candidate JP-900 i.e. a aviation fuel having maximum temperature capability of 482C (900F). Specific progress made for the four tasks constituting Del...

R. J. Santoro

2000-01-01

118

Internal Combustion Engine with Electrostatic Discharging Fuels.  

National Technical Information Service (NTIS)

The patent relates to an internal combustion engine system in which a mixture of air and fuel droplets which are electrostatically charged to a selective polarity is fed to the engine's chambers. The fuel droplets are of uniform size in the micron range, ...

J. B. Stephens C. G. Miller

1977-01-01

119

Catalytic combustion of heavy partially-vaporized fuels  

NASA Technical Reports Server (NTRS)

An experimental program to demonstrate efficient catalytic combustion of fuel-lean and fuel-rich mixtures of residual fuel and air, and to assess the influence of incomplete fuel vaporization on the performance of a catalytic reactor is being conducted. A 7.5-cm diameter catalytic reactor was designed and will be tested over a matrix of conditions representative of a gas turbine combustor inlet. For each of three test phases, two series of tests with a uniform but poorly vaporized (less than 50 percent) mixture of No. 6 fuel oil and air will be performed. In the first series, the non-vaporized fuel will be contained in a spray of droplets with a Sauter Mean Diameter (SMD) less than 30 microns. In the second series, the non-vaporized fuel will be characterized by a spray SMD approximately equal to 100 microns. The designs of the fuel injection system and the catalytic reactor are described in this paper.

Rosfjord, T. J.

1980-01-01

120

A method of determining combustion gas flow  

NASA Technical Reports Server (NTRS)

Zirconium oxide coating enables the determination of hot gas flow patterns on liquid rocket injector face and baffle surfaces to indicate modifications that will increase performance and improve combustion stability. The coating withstands combustion temperatures and due to the coarse surface and coloring of the coating, shows the hot gas patterns.

Bon Tempi, P. J.

1968-01-01

121

Gas phase kinetics during normal combustion  

NASA Technical Reports Server (NTRS)

The role of gas phase kinetics during combustion was explored in the steady state modeling efforts and in the analysis of ignition phenomena. In both cases it was shown that the combustion characteristics of some high energy ingredients and propellants are strongly affected, if not dictated, by the gas phase reactions which take place.

Price, C. F.; Boggs, T. L.; Eisel, J. L.; Atwood, A. I.; Zurn, D. E.

1980-01-01

122

21 CFR 173.350 - Combustion product gas.  

Code of Federal Regulations, 2010 CFR

...173.350 Combustion product gas. The food additive combustion product gas may be safely used in the...purpose of removing and displacing oxygen in accordance with the following...butane, propane, or natural gas. The combustion...

2010-01-01

123

Characterization of oscillations during premix gas turbine combustion  

SciTech Connect

The use of premix combustion in stationary gas turbines can produce very low levels of NO{sub x} emissions. This benefit is widely recognized, but turbine developers routinely encounter problems with combustion oscillations during the testing of new premix combustors. Because of the associated pressure fluctuations, combustion oscillations must be eliminated in a final combustor design. Eliminating these oscillations is often time-consuming and costly because there is no single approach to solve an oscillation problem. Previous investigations of combustion stability have focused on rocket applications, industrial furnaces, and some aeroengine gas turbines. Comparatively little published data is available for premixed combustion at conditions typical of an industrial gas turbine. In this paper, the authors report experimental observations of oscillations produced by a fuel nozzle typical of industrial gas turbines. Tests are conducted in a specially designed combustor capable of providing the acoustic feedback needed to study oscillations. Tests results are presented for pressures up to 10 atmospheres, theoretical considerations, it is expected that oscillations can be characterized by a nozzle reference velocity, with operating pressure playing a smaller role. This expectation is compared to observed data that shows both the benefits and limitations of characterizing the combustor oscillating behavior in terms of a reference velocity rather than other engine operating parameters. This approach to characterizing oscillations is then used to evaluate how geometric changes to the fuel nozzle will affect the boundary between stable and oscillating combustion.

Richards, G.A.; Janus, M.C. [Federal Energy Technology Center, Morgantown, WV (United States)

1998-04-01

124

Fuel-rich catalytic combustion of a high density fuel  

NASA Technical Reports Server (NTRS)

Fuel-rich catalytic combustion (ER is greater than 4) of the high density fuel exo-tetrahydrocyclopentadiene (JP-10) was studied over the equivalence ratio range 5.0 to 7.6, which yielded combustion temperatures of 1220 to 1120 K. The process produced soot-free gaseous products similar to those obtained with iso-octane and jet-A in previous studies. The measured combustion temperature agreed well with that calculated assuming soot was not a combustion product. The process raised the effective hydrogen/carbon (H/C) ratio from 1.6 to over 2.0, thus significantly improving the combustion properties of the fuel. At an equivalence ratio near 5.0, about 80 percent of the initial fuel carbon was in light gaseous products and about 20 percent in larger condensable molecules. Fuel-rich catalytic combustion has now been studied for three fuels with H/C ratios of 2.25 (iso-octane), 1.92 (jet-A), and 1.6 (JP-10). A comparison of the product distribution of these fuels shows that, in general, the measured concentrations of the combustion products were monotonic functions of the H/C ratio with the exception of hydrogen and ethylene. In these cases, data for JP-10 fell between iso-octane and jet-A rather than beyond jet-A. It is suggested that the ring cross-linking structure of JP-10 may be responsible for this behavior. All the fuels studied showed that the largest amounts of small hydrocarbon molecules and the smallest amounts of large condensable molecules occurred at the lower equivalence ratios. This corresponds to the highest combustion temperatures used in these studies. Although higher temperatures may improve this mix, the temperature is limited. First, the life of the present catalyst would be greatly shortened when operated at temperatures of 1300 K or greater. Second, fuel-rich catalytic combustion does not produce soot because the combustion temperatures used in the experiments were well below the threshold temperature (1350 K) for the formation of soot. Increasing the temperature above this value would remove the soot-free nature of the process. Since all the fuels studied show a similar breakdown of the primary fuel into smaller molecular combustion products, this technique can be applied to all hydrocarbon fuels.

Brabbs, Theodore A.; Merritt, Sylvia A.

1993-01-01

125

Fluidized bed combustion of alternative solid fuels; status, successes and problems of the technology  

Microsoft Academic Search

Fluidized bed combustion can be used for energy production or incineration for almost any material containing carbon, hydrogen and sulphur in a combustible form, whether it be in the form of a solid, liquid, slurry or gas. The technology's fuel flexibility arises from the fact that the fuel is present in the combustor at a low level and is burnt

E. J Anthony

1995-01-01

126

A laboratory approach to obtain suspension combustion data for reuse derived fuels  

Microsoft Academic Search

Laboratory scale measurement of burning rates of entrained RDF samples is discussed. The resulting data are expected to be relevant for estimating the characteristics of (1) pulverized fuel combustion and (2) the suspension fraction of spreader stoker combustion. A furnace is described allowing direct measurement of fuel particle burning times as functions of the parameters of the entraining gas flow.

A. Macek; S. R. Charagundla

1982-01-01

127

Plasma enhancement of combustion of solid fuels  

SciTech Connect

Plasma fuel systems that increase the coal burning efficiency are discussed. The systems were tested for fuel oil-free startup of boilers and stabilizating a pulverized-coal flame in power-generating boilers equipped with different types of burner and burning all types of power-generating coal. Plasma ignition, thermochemical treatment of an air-fuel mixture prior to combustion, and its burning in a power-generating boiler were numerically simulated. Environmental friendliness of the plasma technology was demonstrated.

Askarova, A.S.; Karpenko, E.I.; Messerle, V.E.; Ustimenko, A.B. [Institute of Combustion Problems, Alma Ata (Kazakhstan)

2006-03-15

128

Low-Btu coal-gasification-process design report for Combustion Engineering/Gulf States Utilities coal-gasification demonstration plant. [Natural gas or No. 2 fuel oil to natural gas or No. 2 fuel oil or low Btu gas  

SciTech Connect

This report describes a coal gasification demonstration plant that was designed to retrofit an existing steam boiler. The design uses Combustion Engineering's air blown, atmospheric pressure, entrained flow coal gasification process to produce low-Btu gas and steam for Gulf States Utilities Nelson No. 3 boiler which is rated at a nominal 150 MW of electrical power. Following the retrofit, the boiler, originally designed to fire natural gas or No. 2 oil, will be able to achieve full load power output on natural gas, No. 2 oil, or low-Btu gas. The gasifier and the boiler are integrated, in that the steam generated in the gasifier is combined with steam from the boiler to produce full load. The original contract called for a complete process and mechanical design of the gasification plant. However, the contract was curtailed after the process design was completed, but before the mechanical design was started. Based on the well defined process, but limited mechanical design, a preliminary cost estimate for the installation was completed.

Andrus, H E; Rebula, E; Thibeault, P R; Koucky, R W

1982-06-01

129

Research program on reduced combustion chamber heat loss effects on alternative fuel combustion  

Microsoft Academic Search

A research program was conducted to determine the effects of thermal barriers in the combustion chamber of a diesel engine on the combustion and emissions of selected alternative fuels. Comparison of steady state fuel economy, exhaust emissions, and combustion data of heat insulated, baseline water-cooled, and high compression ratio engines were made using three fuels. Fuels believed to be representative

E. E. Daby; I. J. Garwin; P. H. Havstad; C. E. Hunter

1988-01-01

130

Fuel control system for internal combustion engine  

SciTech Connect

This patent describes a fuel control system for an internal combustion engine having fuel supply means for metering fuel to be supplied to the engine in response to an electric command given by fuel supply command means. The fuel control system consists of: a step motor for driving a fuel metering member of the fuel supply means; learning means for learning the number of steps required for energizing the step motor to move the fuel metering member from an idle position to a full-load position; computing means for computing the number of steps required for the step motor to reach a target load position by dividing in proportion the learned number of steps by a ratio between a target load value of an electric command from the fuel supply command means and a maximum value of the electric command; and drive means for energizing the step motor to achieve the number of steps computed by the computing means.

Koshizawa, T.; Yoshimura, H.; Sugimura, T.

1988-09-27

131

Fuel supplying device for internal combustion engine  

SciTech Connect

A fuel supplying device for an internal combustion engine is disclosed which has a fuel supply passage for introducing fuel fed from a fuel pump at a substantially constant pressure to a fuel injector operative at a predetermined constant pressure. The fuel injector is installed at a congregated portion of engine intake manifolds. A metering valve includes a motor so that the pressure drop is maintained substantially constant by a differential regulator. The metering valve is disposed in an intermediate portion of the fuel supply passage. Calculating means including a servo signal generator calculates an injection flow amount causing a predetermined air/fuel ratio on the basis of signals of various engine running factors. An operational signal output from the servo signal generating circuit of the calculating means is applied to the drive motor means for driving said metering valve to thereby inject fuel into the intake manifolds.

Ishida, T.; Miki, T.; Nakamura, H.; Takamiya, B.

1982-07-13

132

Analysis of acid gas emissions in the combustion of the binder enhanced d-RDF (densified Refuse Derived Fuel) by ion chromatography  

SciTech Connect

The acid gas emissions of combusting d-RDF pellets with sulfur-rich coal were analyzed by ion chromatography and decreased when d-RFD pellets were utilized. The results imply the possibility of using d-RDF pellets to substitute for sulfur-rich coal as fuel, and also substantiate the effectiveness of a binder, calcium hydroxide, in decreasing emissions of SO{sub x}. In order to perform the analysis of the combustion sample, sampling and sample pretreatment methods prior to the IC analysis and the first derivative detection mode in IC are investigated as well. At least two trapping reagents are necessary for collecting acid gases: one for hydrogen halides, and the other for NO{sub x} and SO{sub x}. Factors affecting the absorption of acid gases are studied, and the strength of an oxidizing agent is the main factor affecting the collection of NO{sub X} and SO{sub x}. The absorption preference series of acid gases are determined and the absorption models of acid gases in trapping reagents are derived from the analytical results. To prevent the back-flushing of trapping reagents between impingers when leak-checking, a design for the sampling train is suggested, which can be adopted in sample collections. Several reducing agents are studied for pretreating the sample collected in alkali-permanganate media. Beside the recommendation of the hydrogen peroxide solution in EPA method, methanol and formic acid are worth considering as alternate reducing agents in the pretreatment of alkaline-permanganate media prior to IC analysis. The first derivative conductivity detection mode is developed and used in IC system. It is efficient for the detection and quantification of overlapping peaks as well as being applicable for nonoverlapping peaks.

Jen, J.F.

1988-01-01

133

Diazido alkanes and diazido alkanols as combustion modifiers for liquid hydrocarbon ramjet fuels  

Microsoft Academic Search

This invention relates to liquid-hydrocarbon jet fuels and more particularly to azido additives to liquid-hydrocarbon ramjet fuels. In most liquid-fueled combustors such as the ramjet, the fuel is directly introduced into the upstream flow section of the combustion chamber in the form of sprays of droplets. These droplets subsequently mix with the external gas, heat up, gasify, combust, and thereby

1986-01-01

134

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

135

Exhaust gas purifying system for internal combustion engine  

Microsoft Academic Search

An exhaust gas purifying system for an automobile engine including at least first and second engine cylinder has a shutter valve for interrupting the supply of a combustible air-fuel mixture to the first engine cylinder during a particular engine operating condition, a three-way electromagnetically operated valve for controlling the operation of the shutter valve, and a secondary air supply unit

H. Higashi; K. Iida; H. Shiraishi

1982-01-01

136

Numerical simulation of combustion processes in a gas turbine  

NASA Astrophysics Data System (ADS)

The type of the fuel, upstream and downstream flow conditions, fuel injection and mixing processes together with the geometry of the combustion chamber have a significant effect on efficiency, power, fuel consumption, noise and emission of the gas turbines. These contributions can be considered also in the virtual prototyping of combustion chambers, by which significant amount of time, cost and capacity can be saved. However, the accuracy of these approaches must be within 5-10% for industrial relevancies. Hence, a three dimensional, turbulent flow and gas phase combustion has been modelled in a tubular combustion chamber of a gas turbine with the main goal of comparing the effect of different combustion models and solid wall boundary conditions with real tests. Four combustion models as Eddy Dissipation Model (EDM), Probability Density Function Flamelet Model (PFM), Burning Velocity Model (BVM) and Fluent Non-Premixed Model (FnPM) have been applied beside using k-? turbulence model in the simulations. Three different incoming mass flows were implemented according to the measurements, which originate from Serag-Eldin and Spalding's paper [1.]. Although natural gas has been used in the real tests, methane combustion has been modelled in the simulations, because the dominant component of the burnt natural gas was methane in 93.63%. The results were examined in 3 cross sections at certain axial distances along radii. The closest results to the measurements were provided by FnPM, most probably due to the more accurate thermal boundary conditions at the solid walls. In that case, the temperature differences between the measurements and the simulations were within the 30% error margin in the 100% of the investigated radius on the average, within 10% in the 98.6% and within the 5% in the 79.1%.

Bicsák, György; Hornyák, Anita; Veress, Árpád

2012-11-01

137

Analysis of fuel vaporization, fuel/air mixing, and combustion in lean premixed/prevaporized combustors  

SciTech Connect

Requirements to reduce pollutant emissions from gas turbines used in aircraft propulsion and ground-based power generation have led to consideration of lean premixed/prevaporized (LPP) combustion concepts. This paper describes a series of the LPP combustor analyses performed with KIVA-II, a multi-dimensional CFD code for problems involving sprays, turbulence, and combustion. Modifications to KIVA-II`s boundary condition and chemistry treatments have been made to meet the needs of the present study. The study examines the relationships between fuel vaporization, fuel/air mixing, and combustion in a generic LPP combustor. Parameters considered include: mixer tube diameter, mixer tube length, mixer tube configuration (straight versus converging/diverging tubes), air inlet velocity, air inlet swirl angle, secondary air injection (dilution holes), fuel injection velocity, fuel injection angle, number of fuel injection ports, fuel spray cone angle, and fuel droplet size. Cases have been run with and without combustion to examine the variations in fuel/air mixing and potential for flashback due to the above parameters. The degree of fuel/air mixing is judged by comparing average, minimum, and maximum fuel/air ratios at the exit of the mixer tube, while flame stability is monitored by following the location of the flame front as the solution progresses from ignition to steady state.

Deur, J.M. [NYMA, Inc., Brook Park, OH (United States); Penko, P.F. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center; Cline, M.C. [Los Alamos National Lab., NM (United States)

1995-07-01

138

Internal combustion engine fuel rail assembly joint  

SciTech Connect

This patent describes a fuel rail assembly of an internal combustion engine. It comprises a non-metallic fuel rail containing devices that are part of a fuel injection system of the engine, and also comprising a metal tube which is in fluid communication with a fuel passage in the non-metallic fuel rail and connected with the non-metallic fuel rail by means of a joint, characterized in that the joint comprises a cylindrical metal sleeve that is partially embedded in the non-metallic fuel rail such that a first cylindrical portion of the non-metallic fuel rail lines an interior end portion of the sleeve and is in fluid communication with the fuel passage in the non-metallic fuel rail and such that the sleeve lines the interior of a second cylindrical portion of the non-metallic fuel rail, the metal tube and the first cylindrical portion of the non-metallic fuel rail fit together in a sealed manner to place the metal tube in fluid communication with the fuel passage in the non-metallic fuel rail, the sleeve has another portion that is not embedded in the non-metallic fuel rail, and a retention means coacts with the another axis end segment and with the metal tube to retain the metal tube and the first cylindrical portion of the non-metallic fuel rail fit together in a sealed manner.

Imoehl, W.J.

1992-04-21

139

Combustion Temperature Measurement by Spontaneous Raman Scattering in a Jet-A Fueled Gas Turbine Combustor Sector  

NASA Technical Reports Server (NTRS)

Spontaneous vibrational Raman scattering was used to measure temperature in an aviation combustor sector burning jet fuel. The inlet temperature ranged from 670 K (750 F) to 756 K (900 F) and pressures from 13 to 55 bar. With the exception of a discrepancy that we attribute to soot, good agreement was seen between the Raman-derived temperatures and the theoretical temperatures calculated from the inlet conditions. The technique used to obtain the temperature uses the relationship between the N2 anti-Stokes and Stokes signals, within a given Raman spectrum. The test was performed using a NASA-concept fuel injector and Jet-A fuel over a range of fuel/air ratios. This work represents the first such measurements in a high-pressure, research aero-combustor facility.

Hicks, Yolanda R.; DeGroot, Wilhelmus A.; Locke, Randy J.; Anderson, Robert C.

2002-01-01

140

Combustion and fuel characterization of coal-water fuels  

SciTech Connect

This five-year research project was established to provide sufficient data on coal-water fuel (CWF) chemical, physical, and combustion properties to assess the potential for commercial firing in furnaces designed for gas or oil firing. Extensive laboratory testing was performed at bench-scale, pilot-scale (4 {times} 10{sup 6}Btu/hr) and commercial-scale (25 {times} 10{sup 6} to 50 {times} 10{sup 6}Btu/hr) on a cross-section of CWFs. Fuel performance characteristics were assessed with respect to coal properties, level of coal beneficiation, and slurry formulation. The performance of four generic burner designs was also assessed. Boiler performance design models were applied to analyze the impacts associated with conversion of seven different generic unit designs to CWF firing. Equipment modifications, operating limitations, and retrofit costs were determined for each design when utilizing several CWFs. Unit performance analyses showed significantly better load capacity for utility and industrial boilers as the CWF feed coal ash content is reduced to 5% or 2.6%. In general, utility units had more attractive capacity limits and retrofit costs than the industrial boilers and process heaters studied. Economic analyses indicated that conversion to CWF firing generally becomes feasible when differential fuel costs are above $1.00/10{sup 6}Btu. 60 figs., 24 tabs.

Chow, O.K.; Gralton, G.W.; Lachowicz, Y.V.; Laflesh, R.C.; Levasseur, A.A.; Liljedahl, G.N.

1989-02-01

141

Diesel engine combustion and emissions from fuel to exhaust aftertreatment. SP-1113  

SciTech Connect

There are many dimensions involved in any study of Diesel Engine Emissions. These dimensions include: the fuel used, how the fuel is presented into the combustion chamber, how the air is presented into the combustion chamber, the actual process of combustion and emissions formation, the treatment of the emissions after combustion, and the test methods used to quantify the emissions. All of these dimensions are covered in this publication. The fuel topics include: plant oil based fuels and gas dissolved in fuel oil. The air delivery to the combustion chamber is effected by both port performance and geometry and ambient conditions and these topics are included. The thermodynamics of the combustion process and modeling are included in this publication. Aftertreatment is included with a paper on particulate filters. A correlation study using the ISO8178 testing method is also included. All nine papers have been processed separately for inclusion on the database.

NONE

1995-12-31

142

Hybrid combustion with metallized fuels  

NASA Technical Reports Server (NTRS)

A chemical method of adding certain catalysts to improve the degradation process of a solid fuel is discussed. Thermogravimetric (TGA) analysis used to study the fundamental degradation behavior of a typical hybrid fuel (HTPB) shows that high surface temperatures increase the degradation rate. Fuels were tested in a laboratory-scale experimental hybrid rocket and their behavior was compared to a baseline behavior of HTPB fuel regression rates. It was found that a small amount of metal powder added to the fuel can significantly increase the regression rates.

Yi, Jianwen; Wygle, Brian S.; Bates, Ronald W.; Jones, Michael D.; Ramohalli, Kumar

1993-01-01

143

Apparatus and method for gas turbine active combustion control system  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

144

Combustion of Illinois coals and chars with natural gas  

SciTech Connect

There are applications where the combined combustion of coal and natural gas offers potential advantages over the use of either coal or natural gas alone. For example, low volatile coals or low volatile chars derived from treatment or gasification processes can be of limited use during to their poor flammability characteristics. However, the use of natural gas in conjunction with the solid fuel can provide the necessary volatiles'' to enhance the combustion. In addition, natural gas provides a clean fuel source of fuel which, in cofiring situations, can extend the usefulness of coals with high sulfur content. The addition of natural gas may reduce SO{sub x} emission through increased sulfur retention in the ash and reduce NO{sub x} emissions by varying local stoichiometry and temperature levels. In this research program, studies of combined coal and natural gas combustion will provide particle ignition, burnout rates and ash characterization, that will help clarify the effect of coal and natural gas and identify the controlling parameters and mechanisms.

Buckius, R.O.

1991-01-01

145

Research Program on Reduced Combustion Chamber Heat Loss Effects on Alternative Fuel Combustion.  

National Technical Information Service (NTIS)

A research program was conducted to determine the effects of thermal barriers in the combustion chamber of a diesel engine on the combustion and emissions of selected alternative fuels. Comparison of steady state fuel economy, exhaust emissions, and combu...

E. E. Daby, I. J. Garwin, P. H. Havstad, C. E. Hunter

1988-01-01

146

Catalytic combustion with incompletely vaporized residual fuel  

NASA Technical Reports Server (NTRS)

Catalytic combustion of fuel lean mixtures of incompletely vaporized residual fuel and air was investigated. The 7.6 cm diameter, graded cell reactor was constructed from zirconia spinel substrate and catalyzed with a noble metal catalyst. Streams of luminous particles exited the rector as a result of fuel deposition and carbonization on the substrate. Similar results were obtained with blends of No. 6 and No. 2 oil. Blends of shale residual oil and No. 2 oil resulted in stable operation. In shale oil blends the combustor performance degraded with a reduced degree of fuel vaporization. In tests performed with No. 2 oil a similar effect was observed.

Rosfjord, T. J.

1981-01-01

147

Fuel-rich catalytic combustion of a high density fuel  

SciTech Connect

Fuel-rich catalytic combustion (ER is greater than 4) of the high density fuel exo-tetrahydrocyclopentadiene (JP-10) was studied over the equivalence ratio range 5.0 to 7.6, which yielded combustion temperatures of 1220 to 1120 K. The process produced soot-free gaseous products similar to those obtained with iso-octane and jet-A in previous studies. The measured combustion temperature agreed well with that calculated assuming soot was not a combustion product. The process raised the effective hydrogen/carbon (H/C) ratio from 1.6 to over 2.0, thus significantly improving the combustion properties of the fuel. At an equivalence ratio near 5.0, about 80 percent of the initial fuel carbon was in light gaseous products and about 20 percent in larger condensable molecules. Fuel-rich catalytic combustion has now been studied for three fuels with H/C ratios of 2.25 (iso-octane), 1.92 (jet-A), and 1.6 (JP-10). A comparison of the product distribution of these fuels shows that, in general, the measured concentrations of the combustion products were monotonic functions of the H/C ratio with the exception of hydrogen and ethylene. In these cases, data for JP-10 fell between iso-octane and jet-A rather than beyond jet-A. It is suggested that the ring cross-linking structure of JP-10 may be responsible for this behavior. All the fuels studied showed that the largest amounts of small hydrocarbon molecules and the smallest amounts of large condensable molecules occurred at the lower equivalence ratios. This corresponds to the highest combustion temperatures used in these studies. Although higher temperatures may improve this mix, the temperature is limited. First, the life of the present catalyst would be greatly shortened when operated at temperatures of 1300 K or greater. Second, fuel-rich catalytic combustion does not produce soot because the combustion temperatures used in the experiments were well below the threshold temperature (1350 K) for the formation of soot.

Brabbs, T.A.; Merritt, S.A.

1993-07-01

148

Fuel and Combustion Characteristics of Organic Wastes  

NASA Astrophysics Data System (ADS)

From a viewpoint of environmental preservation and resource protection, the recycling of wastes has been promoting. Expectations to new energy resource are growing by decrease of fossil fuel. Biomass is one of new energies for prevent global warning. This study is an attempt to burn biomass lamps made from residues in order to thermally recycle waste products of drink industries. The pyrolytic properties of shochu dregs and used tea leaves were observed by thermo-gravimertic analysis (TG) to obtained fundamental data of drink waste pyrolysis. It observed that shochu dregs pyrolyze under lower temperature than used tea leaves. These wastes were compressed by hot press apparatus in the temperature range from 140 to 180 °C for use as Bio-fuel (BF). The combustion behavior of BF was observed in fall-type electric furnace, where video-recording was carried out at sequential steps, such as ignition, visible envelope flame combustion and char combustion to obtain combustion characteristics such as ignition delay, visible flame combustion time and char combustion time.

Namba, Kunihiko; Ida, Tamio

149

Pressure Effects in Droplet Combustion of Miscible Binary Fuels  

NASA Technical Reports Server (NTRS)

The objective of this research is to improve understanding of the combustion of binary fuel mixtures in the vicinity of the critical point. Fiber-supported droplets of mixtures of n-heptane and n-hexadecane, initially 1 mm in diameter, were burned in room-temperature air at pressures from 1 MPa to 6 MPa under free-fall microgravity conditions. For most mixtures the total burning time was observed to achieve a minimum value at pressures well above the critical pressure of either of the pure fuels. This behavior is explained in terms of critical mixing conditions of a ternary system consisting of the two fuels and nitrogen. The importance of inert-gas dissolution in the liquid fuel near the critical point is thereby re-emphasized, and nonmonotonic dependence of dissolution on initial fuel composition is demonstrated. The results provide information that can be used to estimate high-pressure burning rates of fuel mixtures.

Mikami, Masato; Habara, Osamu; Kono, Michikata; Sato, Jun-Ichi; Dietrich, Daniel L.; Williams, Forman A.

1997-01-01

150

Combustion characteristics of hydrogen-carbon monoxide based gaseous fuels  

NASA Technical Reports Server (NTRS)

The results of trials with a staged combustor designed to use coal-derived gaseous fuels and reduce the NO(x) emissions from nitrogen-bound fuels to 75 ppm and 37 ppm without bound nitrogen in 15% O2 are reported. The combustor was outfitted with primary zone regenerative cooling, wherein the air cooling the primary zone was passed into the combustor at 900 F and mixed with the fuel. The increase in the primary air inlet temperature eliminated flashback and autoignition, lowered the levels of CO, unburned hydrocarbons, and smoke, and kept combustion efficiencies to the 99% level. The combustor was also equipped with dual fuel injection to test various combinations of liquid/gas fuel mixtures. Low NO(x) emissions were produced burning both Lurgi and Winkler gases, regardless of the inlet pressure and temperature conditions. Evaluation of methanation of medium energy gases is recommended for providing a fuel with low NO(x) characteristics.

White, D. J.; Kubasco, A. J.; Lecren, R. T.; Notardonato, J. J.

1982-01-01

151

ON-LINE MEASUREMENT OF NITROUS OXIDE FROM COMBUSTION SOURCES BY AUTOMATED GAS CHROMATOGRAPHY  

EPA Science Inventory

The paper discusses on-line measurement of nitrous oxide (N2O) from combustion sources by automated gas chromatography. ossil fuel combustion is suspected of contributing to measured increases in the ambient concentrations of N2O. haracterization of N2O emissions from fossil fuel...

152

Fuel-cycle greenhouse gas emissions from alternative fuels in Australian heavy vehicles  

Microsoft Academic Search

This paper quantifies the expected pre-combustion and combustion emissions of greenhouse gases from Australian heavy vehicles using alternative fuels. We use the term exbodied emissions for these full fuel-cycle emissions. The fuels examined are low sulfur diesel (LSD), ultra-low sulfur diesel (ULS), compressed natural gas (CNG), liquefied natural gas (LNG), liquefied petroleum gas (LPG), ethanol (from lignocellulose), biodiesel and waste

Tom Beer; Tim Grant; David Williams; Harry Watson

2002-01-01

153

Santilli's new fuels as sources of clean combustion  

NASA Astrophysics Data System (ADS)

Molecular combustion or nuclear fission is the conventional source of energy, which are not clean as they generate large amount of green house gas or nuclear waste. Clean energy can be obtained by harnessing renewable energy sources like solar, wind, etc. However, each of these sources has their own limitations and is dependent on geographical locations. The modern day demand of clean, cheap and abundant energy gets fulfilled by the novel fuels that have been developed through hadronic mechanics/chemistry. In the present paper, a short review on such novel fuels like Hadronic energy of non-nuclear type (combustion of MagneGas) and nuclear type (intermediate controlled nuclear fusion and particle type like stimulated neutron decay) has been presented.

Sarma, Indrani B. Das

2013-10-01

154

Extinction of model fuels with anomalous pressure dependence of the combustion velocity  

SciTech Connect

This article investigates the regimes of combustion of model fuels with a drop in pressure. The following fuel compositions were examined: a reference composition consisting of a model nitroglycerine fuel, nitroglycerine fuel with a 2% additive of lead and copper compounds, and nitroglycerine with the addition of 1% compound of lead. The temperature gradient in the gas near the combustion surface was determined from the temperature profile. The results indicate that when the pressure boundary for the change in combustion mechanisms is crossed during the pressure drop, the conditions for extinguishing the fuel are considerably eased. It is concluded that the investigation of fuel combustion accompanying a pressure drop permits the obtaining of additional data and enables the understanding of the combustion mechanism at constant pressure.

Marshakov, V.N.; Melik-Gaikazov, G.V.

1983-09-01

155

Atmospheric Sulfur and Fossil Fuel Combustion  

Microsoft Academic Search

Sulfate-chloride ratios in ice samples from the Greenland ice sheet indicate that the combustion of fossil fuels is now introducing slightly more sulfur into the atmosphere than such natural processes as volcanism and the oxidation of hydrogen sulfide derived from organic matter. The amount of sulfate co-varies with the amount of lead in the recent glacial strata, which fact suggests

Minoru Koide; Edward D. Goldberg

1971-01-01

156

FUEL NOX CONTROL BY CATALYTIC COMBUSTION  

EPA Science Inventory

The report gives results of an experimental study to: (1) define operating conditions for catalytic combustors that give low levels of NOx emissions for fuelbound nitrogen compounds, and (2) quantitatively determine the fate of fuel nitrogen during catalytic combustion. Tests wer...

157

LOW NOx COMBUSTION OF BIOMASS FUELS  

Microsoft Academic Search

Biomass combustion can make use of many waste products found in the timber, manufactured wood products, and agricultural industries. It not only provides a source of essentially free fuel, but can also eliminate many of the disposal problems associated with these by-products. The environmental regulations faced by industry are one of the primary governing factors that must be addressed when

S. Drennan

158

Combustion of Condensed Phase Alternative Fuels in an Acoustic Field  

Microsoft Academic Search

This experimental study focused on fuel droplet combustion characteristics for various liquids during exposure to external acoustical perturbations. Emphasis in the present study was placed on the combustion of a number of alternative liquid fuels, including ethanol, methanol, aviation fuels, and blends of aviation fuel and liquid synthetic fuel derived from coal gasification via the Fischer-Tropsch process. The study examined

Juan Rodriguez; Hann-Shin Mao; Sophonias Teshome; Alec Pezeshkian; Owen Smith; Ann Karagozian

2007-01-01

159

Investigation of trapped vortex combustion using hydrogen-rich fuels  

NASA Astrophysics Data System (ADS)

The combustion process of a fuel is a challenging subject when it comes to analyze its performance and resultant emissions. The main task of this study is to optimize the selection of a hydrogen-rich fuel based on its performance and emissions. Computational Fluid Dynamics analysis is performed to test the combustion performance and emissions from the vortex trapped combustor when natural gas fuel (methane) is replaced with renewable and alternative fuels such as hydrogen and synthesis gas. Correlation graphs for the trapped vortex combustor performance and NOx, CO, and CO2 emissions for various types of fuels with different compositions and heat of combustion values were established. Methane, Hydrogen and 10 different syngas fuels were analyzed in this study using computational fluid dynamics numerical method. The trapped vortex combustor that represents an efficient and compact combustor for flame stability was investigated. The TVC consists of a fore body and two after body disks. These components are all encircled with a Pyrex tube. The purpose of the after body disks is to create the vortex wakes that will enhance the combustion process and minimize the NOx emissions. The TVC CFD model was validated by comparing the CFD model results using propane fuel with existing experimental results that were established in Rome, Italy. The static temperature distribution and NOx, CO emissions, combustor efficiency and total pressure drop results of the three dimensional CFD model were similar to the experimental data. Effects of H2/CO and H2/CH4 ratios and the mass fraction of each constituent of syngas fuels and Hydrogen-Methane fuel mixture on the TVC performance and emissions were investigated. Moreover, the fuel injector Reynolds number and Lower heating values for Methane, Hydrogen and 10 syngas fuels on the TVC performance and emissions were also investigated. Correlation plots for the NOx, CO and CO2 emissions versus the fuel injector Reynolds number and lower heating value were established. These correlation curves can be used as a fair design diagram to optimize the fuel selection process for aerospace and electrical power plant applications.

Zbeeb, Khaled

160

Ash deposition and composition resulting from the combustion of lignite coals combined with fuel oil and natural gas  

Microsoft Academic Search

The search for alternative fuels for use by American Industry has led to the development of coal-oil mixtures and more recently coal-water mixtures. Ash handling equipment costs for retrofitted units represents a substantial percentage of the total capital investment and often contributes to making conversion to coal-oil mixtures economically unattractive. This paper reports on the findings of ash deposition and

V. A. Cundy; N. Estep; D. Maples

1983-01-01

161

Effect of intake valve swirl on fuel-gas mixing and subsequent combustion in a CAI engine  

Microsoft Academic Search

A fully three-dimensional model was used to investigate the optimal value for intake valve lift in a CAI engine. Uniform mixing\\u000a in the engine is a key parameter that affects the auto-ignition reliability and thermal efficiency. The method of intake of\\u000a the air supply often determines the uniformity (or quality) of the fuel-air mixture. In this paper, four strategies were

J. N. Kim; H. Y. Kim; S. S. Yoon; S. D. Sa

2008-01-01

162

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

PubMed

Since the use of diesel engines is still increasing, the contribution of their incomplete combustion products to air pollution is becoming ever more important. The presence of irritating and genotoxic substances in both the gas phase and the particulate phase constituents is considered to have significant health implications. The quantity of soot particles and the particle-associated organics emitted from the tail pipe of a diesel-powered vehicle depend primarily on the engine type and combustion conditions but also on fuel properties. The quantity of soot particles in the emissions is determined by the balance between the rate of formation and subsequent oxidation. Organics are absorbed onto carbon cores in the cylinder, in the exhaust system, in the atmosphere and even on the filter during sample collection. Diesel fuel contains polycyclic aromatic hydrocarbons (PAHs) and some alkyl derivatives. Both groups of compounds may survive the combustion process. PAHs are formed by the combustion of crankcase oil or may be resuspended from engine and/or exhaust deposits. The conversion of parent PAHs to oxygenated and nitrated PAHs in the combustion chamber or in the exhaust system is related to the vast amount of excess combustion air that is supplied to the engine and the high combustion temperature. Whether the occurrence of these derivatives is characteristic for the composition of diesel engine exhaust remains to be ascertained. After the emission of the particles, their properties may change because of atmospheric processes such as aging and resuspension. The particle-associated organics may also be subject to (photo)chemical conversions or the components may change during sampling and analysis. Measurement of emissions of incomplete combustion products as determined on a chassis dynamometer provides knowledge of the chemical composition of the particle-associated organics. This knowledge is useful as a basis for a toxicological evaluation of the health hazards of diesel engine emissions. PMID:1383162

Scheepers, P T; Bos, R P

1992-01-01

163

The potential for clean energy production using oxy-fuel combustion and integrated pollutant removal  

SciTech Connect

Effective remediation of flue gas produced by an oxy-fuel coal combustion process has been proven at bench scale in the course of cooperative research between USDOE’s Albany Research Center (ARC) and Jupiter Oxygen Corporation. All combustion gas pollutants were captured, including CO2 which was compressed to a liquefied state suitable for sequestration. Current laboratory-scale research and the future of combined oxy-fuel/IPR systems are discussed.

Ochs, Thomas L.; Oryshchyn, Danylo B.; Weber, Thomas (Jupiter Oxygen Corporation, Schiller Park, IL 60176).; Summers, Cathy A.

2005-05-01

164

Study on Combustion Oscillation of Premixed Flame with Pilot Fuel at Elevated Pressures  

NASA Astrophysics Data System (ADS)

Acoustically-coupled combustion oscillation is studied for premixed flame with pilot fuel to be used in gas turbine combustors. Premixed gas is passed through swirl vanes and burnt with the centrally injected pilot fuel. The dependencies of pressure, fuel to air ratio, premixed fuel rate, inlet velocity and air temperature on the combustion oscillation are investigated. Two kinds of oscillation modes of ˜100Hz and ˜350Hz are activated according to inlet velocities. Fluctuating pressures are amplified when the premixed fuel rate is over ˜80% at elevated pressures. The fluctuating pressure peak moves to a higher premixed fuel ratio region with increased pressure or fuel to air ratio for the Helmholz type mode. Combustion oscillation occurs when the pilot fuel velocity is changed proportionally with the flame length.

Ohtsuka, Masaya; Yoshida, Shohei; Hirata, Yoshitaka; Kobayashi, Nariyoshi

165

Combustion Characteristics of Oxy-fuel Burners for CO2 Capturing Boilers  

NASA Astrophysics Data System (ADS)

Oxy-fuel boilers have been developed to capture CO2 from the exhaust gas. A 50 kW class model burner has been developed and tested in a furnace type boiler. The burner has been scaled up to 0.5 and 3 MW class for fire-tube type boilers. The burners are commonly laid out in a coaxial type to effectively heat the combustion chamber of boilers. Burners are devised to support air and oxy-fuel combustion modes for the retrofitting scenario. FGR (flue gas recirculation) has been tried during the scale-up procedure. Oxy-fuel combustion yields stretched flame to uniformly heat the combustion chamber. It also provides the high CO2 concentration, which is over 90% in dry base. However, pure oxy-fuel combustion increases NO concentration, because of the reduced flow rate. The FGR can suppress the thermal NOx induced by the infiltration of the air.

Ahn, Joon; Kim, Hyouck Ju; Choi, Kyu Sung

166

Heavy duty gas turbine combustion tests with simulated low BTU coal gas  

SciTech Connect

This program has the objectives to: A. Parametrically determine the effects of moisture, nitrogen and carbon dioxide as diluents so that the combustion characteristics of many varieties of gasification product gases can be reasonably predicted without physically testing each specific gas composition. B. Determine emissions characteristics including NO, NO{sub x}, CO, levels etc. associated with each of the diluents, and C. Operate with at least two syngas compositions; DOE chosen air-blown and integrated oxygen-blown, to confirm that the combustion characteristics are in line with predictions. As a result of this program: 1. GE Engineering is now confident that the syngas fuels produced by all currently--viable coal gasifiers can be accommodated by the GE advanced (``F`` Technology) combustion system, and 2. For proposed syngas fuels with varying amounts of steam, nitrogen or CO{sub 2} diluent, the combustion and emissions characteristics can be reasonably estimated without undertaking expensive new screening tests for each different fuel.

Ekstrom, T.E.; Battista, R.A.; Belisle, F.H.; Maxwell, G.P.

1993-11-01

167

Near-Zero NOx Combustion Technology for ATS Mercury 50 Gas Turbine  

Microsoft Academic Search

A project to demonstrate a near-zero NOx, catalytic combustion technology for natural gas-fired, industrial gas turbines is described. In a cooperative effort between Solar Turbines Incorporated and Precision Combustion Incorporated (PCI), proof-of-concept rig testing of PCI's fuel-rich catalytic combustion technology has been completed successfully. The primary technical goal of the project was to demonstrate NOx and CO emissions below 5ppm

Kenneth Smith

2004-01-01

168

FUEL FORMULATION EFFECTS ON DIESEL FUEL INJECTION, COMBUSTION, EMISSIONS AND EMISSION CONTROL  

SciTech Connect

This paper describes work under a U.S. DOE sponsored Ultra Clean Fuels project entitled ''Ultra Clean Fuels from Natural Gas,'' Cooperative Agreement No. DE-FC26-01NT41098. In this study we have examined the incremental benefits of moving from low sulfur diesel fuel and ultra low sulfur diesel fuel to an ultra clean fuel, Fischer-Tropsch diesel fuel produced from natural gas. Blending with biodiesel, B100, was also considered. The impact of fuel formulation on fuel injection timing, bulk modulus of compressibility, in-cylinder combustion processes, gaseous and particulate emissions, DPF regeneration temperature and urea-SCR NOx control has been examined. The primary test engine is a 5.9L Cummins ISB, which has been instrumented for in-cylinder combustion analysis and in-cylinder visualization with an engine videoscope. A single-cylinder engine has also been used to examine in detail the impacts of fuel formulation on injection timing in a pump-line-nozzle fueling system, to assist in the interpretation of results from the ISB engine.

Boehman, A; Alam, M; Song, J; Acharya, R; Szybist, J; Zello, V; Miller, K

2003-08-24

169

Plasma-aided solid fuel combustion  

SciTech Connect

Plasma supported solid fuel combustion is promising technology for use in thermal power plants (TPP). The realisation of this technology comprises two main steps. The first is the execution of a numerical simulation and the second involves full-scale trials of plasma supported coal combustion through plasma-fuel systems (PFS) mounted on a TPP boiler. For both the numerical simulation and the full-scale trials, the boiler of 200 MW power of Gusinoozersk TPP (Russia) was selected. The optimization of the combustion of low-rank coals using plasma technology is described, together with the potential of this technology for the general optimization of the coal burning process. Numerical simulation and full-scale trials have enabled technological recommendations for improvement of existing conventional TPP to be made. PFS have been tested for boilers plasma start-up and flame stabilization in different countries at 27 power boilers steam productivity of 75-670 tons per hour (TPH) equipped with different type of pulverised coal burners. At PFS testing power coals of all ranks (brown, bituminous, anthracite and their mixtures) were used. Volatile content of them varied from 4 to 50%, ash from 15 to 48% and calorific values from 6700 to 25,100 KJ/kg. In summary, it is concluded that the developed and industrially tested PFS improve coal combustion efficiency and decrease harmful emission from pulverised coal-fired TPP. 9 refs., 14 figs., 2 tabs.

E.I. Karpenko; V.E. Messerle; A.B. Ustimenko ['United Power System of Russia', Gusinoozersk (Russian Federation). Branch Centre of Plasma-Power Technologies of Russian J.S.Co.

2007-07-01

170

Fuel Droplet Burning During Droplet Combustion Experiment  

NASA Technical Reports Server (NTRS)

Fuel ignites and burns in the Droplet Combustion Experiment (DCE) on STS-94 on July 4 1997, MET:2/05:40 (approximate). The DCE was designed to investigate the fundamental combustion aspects of single, isolated droplets under different pressures and ambient oxygen concentrations for a range of droplet sizes varying between 2 and 5 mm. DCE used various fuels -- in drops ranging from 1 mm (0.04 inches) to 5 mm (0.2 inches) -- and mixtures of oxidizers and inert gases to learn more about the physics of combustion in the simplest burning configuration, a sphere. The experiment elapsed time is shown at the bottom of the composite image. The DCE principal investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (1.4MB, 13-second MPEG, screen 320 x 240 pixels; downlinked video, higher quality not available)A still JPG composite of this movie is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300168.html.

2003-01-01

171

Low-temperature combustion of solid fuels in a fluid bed containing a heat sink  

Microsoft Academic Search

A study was made of the influence of particle size, bed temperature, gas velocity and oxygen level on the residence time required to complete combustion of solid fuels, which included various ranks of coal and wood, injected into a fluid bed operating at 1600 F. A simple, well-stirred reactor was used as the basis for modeling the heat-transfer and combustion

R. W. Bryers

1977-01-01

172

Removal of SOx, NOx, and particulate from combusted carbonaceous fuels  

SciTech Connect

The invention is a method for removing sulfur oxides, nitrogen oxides and particulate from the products of combusted carbonaceous fuels. Sulfur oxides, nitrogen oxides and particulate are currently discharged to the atmosphere as flue gas in quantities highly detrimental to the environment. Potassium compounds, as are found in agricultural grade potash, are dispersed throughout the combustion products at the exit of the combustion zone of boilers. The potassium compounds decompose as a result of combustion temperatures in excess of their melting points. The potassium, as an ionic vapor, reacts with the sulfur and nitrogen oxide gases present, to form potassium sulfates, potassium nitrites and potassium nitrates. When the combined products stream, traversing the boiler equipment train, cool sufficiently, the potassium, present in excess, condenses as potassium oxide on the surfaces of the particles present. The larger particles are removed from the non-condensed vapor and gas by the centrifugal and gravitational forces exerted within cyclones. The smaller particles are removed from the non-chargable vapor and gases by the electrostatic charge and attraction created within the precipitator. The dry particles discharged from the cyclones and precipitator are ready for ultimate end use as potash fertilizer without further treatment. The flue gas atmospheric emissions contain only trace quantities of sulfur oxides, nitrogen oxides and particulate.

Dayen, W.R.

1985-09-10

173

A Dual-Line Detection Rayleigh Scattering Diagnostic Technique for the Combustion of Hydrocarbon Fuels and Filtered UV Rayleigh Scattering for Gas Velocity Measurements  

NASA Technical Reports Server (NTRS)

Non-intrusive techniques for the dynamic measurement of gas flow properties such as density, temperature and velocity, are needed in the research leading to the development of new generation high-speed aircraft. Accurate velocity, temperature and density data obtained in ground testing and in-flight measurements can help understand the flow physics leading to transition and turbulence in supersonic, high-altitude flight. Such non-intrusive measurement techniques can also be used to study combustion processes of hydrocarbon fuels in aircraft engines. Reliable, time and space resolved temperature measurements in various combustor configurations can lead to a better understanding of high temperature chemical reaction dynamics thus leading to improved modeling and better prediction of such flows. In view of this, a research program was initiated at Polytechnic University's Aerodynamics Laboratory with support from NASA Lewis Research Center through grants NAG3-1301 and NAG3-1690. The overall objective of this program has been to develop laser-based, non-contact, space- and time-resolved temperature and velocity measurement techniques. In the initial phase of the program a ND:YAG laser-based dual-line Rayleigh scattering technique was developed and tested for the accurate measurement of gas temperature in the presence of background laser glare. Effort was next directed towards the development of a filtered, spectrally-resolved Rayleigh/Mie scattering technique with the objective of developing an interferometric method for time-frozen velocity measurements in high-speed flows utilizing the uv line of an ND:YAG laser and an appropriate molecular absorption filter. This effort included both a search for an appropriate filter material for the 266 nm laser line and the development and testing of several image processing techniques for the fast processing of Fabry-Perot images for velocity and temperature information. Finally, work was also carried out for the development of a new laser-based strain-rate and vorticity technique for the time-resolved measurement of vorticity and strain-rates in turbulent flows.

Otugen, M. Volkan

1997-01-01

174

Oxy-fuel combustion with integrated pollution control  

Microsoft Academic Search

An oxygen fueled integrated pollutant removal and combustion system includes a combustion system and an integrated pollutant removal system. The combustion system includes a furnace having at least one burner that is configured to substantially prevent the introduction of air. An oxygen supply supplies oxygen at a predetermine purity greater than 21 percent and a carbon based fuel supply supplies

Brian R. Patrick; Thomas Lilburn Ochs; Cathy Ann Summers; Danylo B. Oryshchyn; Paul Chandler Turner

2012-01-01

175

Some critical combustion aspects of reformulated heating fuels  

Microsoft Academic Search

The combustion characteristics of six middle distillate oil blends were examined using the controlled combustion testing facilities at the Energy Research Laboratories of the Canada Centre for Minerals and Energy Technologies (CANMET). Test fuels were specifically prepared for a research project to study the impact of changes in commercial heating fuel composition on the combustion performance of a residential heating

S. Win Lee; David P. C. Fung

1995-01-01

176

Use of fluidic oscillator to measure fuel-air ratios of combustion gases  

NASA Technical Reports Server (NTRS)

A fluidic oscillator was investigated for use in measuring fuel-air ratios in hydrocarbon combustion processes. The oscillator was operated with dry exhaust gas from an experimental combustor burning ASTM A-1 fuel. Tests were conducted with fuel-air ratios between 0.015 and 0.031. Fuel-air ratios determined by oscillator frequency were within 0.001 of the values computed from separate flow measurements of the air and fuel.

Riddlebaugh, S. M.

1974-01-01

177

Effect of oxy-combustion flue gas on mercury oxidation.  

PubMed

This study evaluates the effect of the gases present in a typical oxy-coal combustion atmosphere on mercury speciation and compares it with the mercury speciation produced in conventional air combustion atmospheres. The work was performed at laboratory scale at 150 °C. It was found that the minor constituents (SO2, NOx, and HCl) significantly modify the percentages of Hg(2+) in the gas. The influence of these species on mercury oxidation was demostrated when they were tested individually and also when they were blended in different gas compositions, although the effect was different to the sum of their individual effects. Of the minor constituents, NOx were the main species involved in oxidation of mercury. Moreover, it was found that a large concentration of H2O vapor also plays an important role in mercury oxidation. Around 50% of the total mercury was oxidized in atmospheres with H2O vapor concentrations typical of oxy-combustion conditions. When the atmospheres have similar concentrations of SO2, NO, NO2, HCl, and H2O, the proportion of Hg(0)/Hg(2+) is similar regardless of whether CO2 (oxy-fuel combustion) or N2 (air combustion) are the main components of the gas. PMID:24877895

Fernández-Miranda, Nuria; Lopez-Anton, M Antonia; Díaz-Somoano, Mercedes; Martínez-Tarazona, M Rosa

2014-06-17

178

Apparatus for controlling the air fuel mixture of an internal combustion engine  

SciTech Connect

A fuel feeding apparatus for internal combustion engines comprises an area type air flow rate measuring section in which the air flow rate is dependent on the displacement of an air flow rate detecting valve, and a fuel flow rate measuring and distributing section in which a variable orifice defined by a rotor and a stator determines the fuel flow rate proportional to the air flow rate. This apparatus is characterized by the provision of an exhaust gas sensor disposed in the exhaust pipe for the detection of the oxygen concentration of the exhaust gas in order to achieve the complete combustion of fuel in the internal combustion engine, the output signal from the exhaust gas sensor being used to compensate the fuel feeding pressure and a spring force which acts on the pressure difference setting diaphragm of a servo-mechanism.

Harada, H.; Kimata, K.; Nakazeki, T.

1980-06-03

179

Pyrolysis of Polymethylmethacrylate during Combustion in a Solid Fuel Combustion Chamber.  

National Technical Information Service (NTIS)

The report deals with the pyrolysis of the polymer polymethylmethacrylate during combustion in a Solid Fuel Combustion Chamber (SFCC). It includes both a literature study and experimental results. The applicability of bulk pyrolysis experiments, for linea...

J. P. de Wilde

1987-01-01

180

Investigation of Combustion Characteristics of Douglas Fir Hogged Fuel.  

National Technical Information Service (NTIS)

The initial results are presented of studies of the combustion characteristics of Douglas Fir bark (hogged fuel) as burned in a spreader-stoker experimental test facility. The project was funded by ERDA and attempts to determine combustion characteristics...

D. C. Junge

1978-01-01

181

Method for in-flight combustion of carbonaceous fuels  

SciTech Connect

An apparatus and method for combusting carbonaceous fuels includes a reaction chamber defining a reaction zone and means for injecting fuel and oxidizer gas in a manner to produce in the reaction zone a wheel-type flow of the fuel-gas mixture. In preferred embodiments, the high velocity wheel-type flow operates to suspend fuel or other reactant particles in the swirling gas for residence times required for substantially complete reaction of the particles prior to the particles impinging against the walls of the reaction chamber. High angular veocities and the resulting centrifugal forces operate to remove substantially all slag from the gas as it approaches the downstream end of the reaction chamber. Operating temperatures are maintained at a level to avoid excessive volatilization of slag and thereby promote separation of liquid slag from the gaseous reaction products. Dense phase flow is employed for transporting pulverized reactants such as coal to the reaction chamber and injecting the reactants through a pintle fuel injector.

Burge, H. L.; Hardgrove, J. A.; Krieve, W. F.

1980-08-12

182

Vaporization and combustion of fuel droplets at supercritical conditions  

NASA Technical Reports Server (NTRS)

Vaporization and combustion liquid-fuel droplets in both sub- and super-critical environments have been examined. The formulation is based on the complete conservation equations for both gas and liquid phases, and accommodates finite-rate chemical kinetics and a full treatment of liquid-vapor phase equilibrium at the droplet surface. The governing equations and the associated interface boundary conditions are solved numerically using a fully coupled, implicit scheme with the dual time-stepping integration technique. The model is capable of treating the entire droplet history, including the transition from the subcritical to the supercritical state. As a specific example, the combustion of n-pentane fuel droplets in air is studied for pressures of 5-140 atm. In addition, the dynamic responses of droplet vaporization and combustion to ambient-pressure oscillations are investigated. Results indicate that the droplet gasification and burning mechanisms depend greatly on the ambient pressure. In particular, a rapid enlargement of the vaporization and combustion responses occurs when the droplet surface reaches its critical point, mainly due to the strong variations of latent heat of vaporization and thermophysical properties at the critical state.

Yang, Vigor

1991-01-01

183

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

DOEpatents

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

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

2013-12-17

184

Fuel-rich catalytic combustion of Jet-A fuel-equivalence ratios 5.0 to 8.0  

NASA Technical Reports Server (NTRS)

Fuel-rich catalytic combustion (E.R. greater than 5.0) is a unique technique for preheating a hydrocarbon fuel to temperatures much higher than those obtained by conventional heat exchangers. In addition to producing very reactive molecules, the process upgrades the structure of the fuel by the formation of hydrogen and smaller hydrocarbons and produces a cleaner burning fuel by removing some of the fuel carbon from the soot formation chain. With fuel-rich catalytic combustion as the first stage of a two stage combustion system, enhanced fuel properties can be utilized by both high speed engines, where time for ignition and complete combustion is limited, and engines where emission of thermal NO sub x is critical. Two-stage combustion (rich-lean) has been shown to be effective for NO sub x reduction in stationary burners where residence times are long enough to burn-up the soot formed in the first stage. Such residence times are not available in aircraft engines. Thus, the soot-free nature of the present process is critical for high speed engines. The successful application of fuel-rich catalytic combustion to Jet-A, a multicomponent fuel used in gas turbine combustors, is discusssed.

Brabbs, Theodore A.; Gracia-Salcedo, Carmen M.

1989-01-01

185

Demonstration of catalytic combustion with residual fuel  

NASA Astrophysics Data System (ADS)

An experimental program was conducted to demonstrate catalytic combustion of a residual fuel oil. Three catalytic reactors, including a baseline configuration and two backup configurations based on baseline test results, were operated on No. 6 fuel oil. All reactors were multielement configurations consisting of ceramic honeycomb catalyzed with palladium on stabilized alumina. Stable operation on residual oil was demonstrated with the baseline configuration at a reactor inlet temperature of about 825 K (1025 F). At low inlet temperature, operation was precluded by apparent plugging of the catalytic reactor with residual oil. Reduced plugging tendency was demonstrated in the backup reactors by increasing the size of the catalyst channels at the reactor inlet, but plugging still occurred at inlet temperature below 725 K (845 F). Operation at the original design inlet temperature of 589 K (600 F) could not be demonstrated. Combustion efficiency above 99.5% was obtained with less than 5% reactor pressure drop. Thermally formed NO sub x levels were very low (less than 0.5 g NO2/kg fuel) but nearly 100% conversion of fuel-bound nitrogen to NO sub x was observed.

Dodds, W. J.; Ekstedt, E. E.

1981-08-01

186

Demonstration of catalytic combustion with residual fuel  

NASA Technical Reports Server (NTRS)

An experimental program was conducted to demonstrate catalytic combustion of a residual fuel oil. Three catalytic reactors, including a baseline configuration and two backup configurations based on baseline test results, were operated on No. 6 fuel oil. All reactors were multielement configurations consisting of ceramic honeycomb catalyzed with palladium on stabilized alumina. Stable operation on residual oil was demonstrated with the baseline configuration at a reactor inlet temperature of about 825 K (1025 F). At low inlet temperature, operation was precluded by apparent plugging of the catalytic reactor with residual oil. Reduced plugging tendency was demonstrated in the backup reactors by increasing the size of the catalyst channels at the reactor inlet, but plugging still occurred at inlet temperature below 725 K (845 F). Operation at the original design inlet temperature of 589 K (600 F) could not be demonstrated. Combustion efficiency above 99.5% was obtained with less than 5% reactor pressure drop. Thermally formed NO sub x levels were very low (less than 0.5 g NO2/kg fuel) but nearly 100% conversion of fuel-bound nitrogen to NO sub x was observed.

Dodds, W. J.; Ekstedt, E. E.

1981-01-01

187

GAS TURBINE REHEAT USING IN SITU COMBUSTION  

SciTech Connect

In situ reheat is an alternative to traditional gas turbine reheat design in which fuel is fed through airfoils rather than in a bulky discrete combustor separating HP and LP turbines. The goals are to achieve increased power output and/or efficiency without higher emissions. In this program the scientific basis for achieving burnout with low emissions has been explored. In Task 1, Blade Path Aerodynamics, design options were evaluated using CFD in terms of burnout, increase of power output, and possible hot streaking. It was concluded that Vane 1 injection in a conventional 4-stage turbine was preferred. Vane 2 injection after vane 1 injection was possible, but of marginal benefit. In Task 2, Combustion and Emissions, detailed chemical kinetics modeling, validated by Task 3, Sub-Scale Testing, experiments, resulted in the same conclusions, with the added conclusion that some increase in emissions was expected. In Task 4, Conceptual Design and Development Plan, Siemens Westinghouse power cycle analysis software was used to evaluate alternative in situ reheat design options. Only single stage reheat, via vane 1, was found to have merit, consistent with prior Tasks. Unifying the results of all the tasks, a conceptual design for single stage reheat utilizing 24 holes, 1.8 mm diameter, at the trailing edge of vane 1 is presented. A development plan is presented.

D.M. Bachovchin; T.E. Lippert; R.A. Newby P.G.A. Cizmas

2004-05-17

188

Gasification Evaluation of Gas Turbine Combustion  

SciTech Connect

This report provides a preliminary assessment of the potential for use in gas turbines and reciprocating gas engines of gases derived from biomass by pyrolysis or partial oxidation with air. Consideration was given to the use of mixtures of these gases with natural gas as a means of improving heating value and ensuring a steady gas supply. Gas from biomass, and mixtures with natural gas, were compared with natural gas reformates from low temperature partial oxidation or steam reforming. The properties of such reformates were based on computations of gas properties using the ChemCAD computational tools and energy inputs derived from known engine parameters. In general, the biomass derived fuels compare well with reformates, so far as can be judged without engine testing. Mild reforming has potential to produce a more uniform quality of fuel gas from very variable qualities of natural gas, and could possibly be applied to gas from biomass to eliminate organic gases and condensibles other than methane.

Battelle

2003-12-30

189

Experimental gas-fired pulse-combustion studies  

NASA Technical Reports Server (NTRS)

Experimental studies conducted at Argonne National Laboratory on a gas-fired, water-cooled, Helmholtz-type pulse combustion burner are discussed. In addition to the experimental work, information is presented on the evolution of pulse combustion, the types of pulse combustion burners and their applications, and the types of fuels used. Also included is a survey of other pertinent studies of gas-fired pulse combustion. The burner used in the Argonne research effort was equipped with adjustable air and gas flapper valves and was operated stably over a heat-input range of 30,000 to 200,000 Btu/h. The burner's overall heat transfer in the pulsating mode was 22 to 31% higher than when the unit was operated in the steady mode. Important phenomena discussed include (1) effects on performance produced by inserting a corebustor to change tailpipe diameter, (2) effects observed following addition of an air-inlet decoupling chamber to the unit, and (3) occurrence of carbon monoxide in the exhaust gas.

Blomquist, C. A.

1982-01-01

190

Numerical analysis of supersonic combustion ramjet with upstream fuel injection  

Microsoft Academic Search

This paper describes possible fuel injection scheme for airbreathing engines that use hydrocarbon fuels. The basic idea is to inject fuel at the spike tip of the supersonic inlet to achieve mixing and combustion efficiency with a limited length combustion chamber. A numerical code, able to solve the full Navier-Stokes equations in turbulent and reacting flows, is employed to obtain

Raffaele Savino; Giuseppe Pezzella

2003-01-01

191

Investigation of combustion characteristics of Douglas fir hogged fuel  

Microsoft Academic Search

The initial results are presented of studies of the combustion characteristics of Douglas Fir bark (hogged fuel) as burned in a spreader-stoker experimental test facility. The project was funded by ERDA and attempts to determine combustion characteristics for fuels burned in controlled conditions. Independent variables include wood size, wood moisture content, underfire\\/overfire air ratios, and fuel to air ratios. The

Junge

1978-01-01

192

Recent advances in the combustion of water fuel emulsion  

Microsoft Academic Search

Recent advances in the combustion of water fuel emulsion which consists of base fuel and water doped with or without a trace content of surfactant are reviewed. The focus is on the fundamental mechanism relevant to the micro-explosion phenomena leading to the secondary atomization which is not common to the combustion of pure fuel. Described at first are the kinetic

T. Kadota; H. Yamasaki

2002-01-01

193

A study of the combustion and emission characteristics of compressed-natural-gas direct-injection stratified combustion using a rapid-compression-machine  

Microsoft Academic Search

The objective of the present study is to determine the characteristics of combustion and emissions of compressed-natural-gas (CNG) direct-injection combustion using a rapid-compression-machine which has a compression ratio of 10 and a disc-shaped combustion chamber. Combustion and emission characteristics are compared for three types of fuel injection (single side, parallel side and opposed side injection) and a homogeneous mixture. The

S. Shiga; S. Ozone; H. T. C. Machacon; T. Karasawa; H. Nakamura; T. Ueda; N. Jingu; Z. Huang; M. Tsue; M. Kono

2002-01-01

194

Effects of fuel nozzle design on performance of an experimental annular combustor using natural gas fuel  

NASA Technical Reports Server (NTRS)

Tests of various fuel nozzles were conducted with natural gas fuel in a full-annulus combustor. The nozzles were designed to provide either axial, angled, or radial fuel injection. Each fuel nozzle was evaluated by measuring combustion efficiency at relatively severe combustor operating conditions. Combustor blowout and altitude ignition tests were also used to evaluate nozzle designs. Results indicate that angled injection gave higher combustion efficiency, less tendency toward combustion instability, and altitude relight characteristics equal to or superior to those of the other fuel nozzles that were tested.

Wear, J. D.; Schultz, D. F.

1972-01-01

195

Ignition and combustion of fuel droplets and the ignition of premixed fuels by hot cylindrical surfaces  

Microsoft Academic Search

Two types of combustion problems relevant to the gasification, ignition and combustion of fuels in combustion chambers using sprays are theoretically analyzed using mathematical and numerical techniques. The problem of the vaporization, ignition and subsequent combustion of a fuel droplet in a hot convective flow at atmospheric or moderately elevated pressures is analyzed using boundary layer theory around a spherical

R. H. Rangel; A. C. Fernandez-Pello; A. K. Oppenheim

1985-01-01

196

Aviation-fuel property effects on combustion  

NASA Technical Reports Server (NTRS)

The fuel chemical property influence on a gas turbine combustor was studied using 25 test fuels. Fuel physical properties were de-emphasized by using fuel injectors which produce highly-atomized, and hence rapidly vaporizing sprays. A substantial fuel spray characterization effort was conducted to allow selection of nozzles which assured that such sprays were achieved for all fuels. The fuels were specified to cover the following wide ranges of chemical properties: hydrogen, 9.1 to 15 (wt) pct; total aromatics, 0 to 100 (vol) pct; and naphthalene, 0 to 30 (vol) pct. standard fuels (e.g., Jet A, JP4), speciality products (e.g., decalin, xylene tower bottoms) and special fuel blends were included. The latter group included six, 4-component blends prepared to achieve parametric variations in fuel hydrogen, total aromatics and naphthalene contents. The principle influences of fuel chemical properties on the combustor behavior were reflected by the radiation, liner temperature, and exhaust smoke number (or equivalently, soot number density) data. Test results indicated that naphthalene content strongly influenced the radiative heat load while parametric variations in total aromatics did not.

Rosfjord, T. J.

1984-01-01

197

The origin of organic pollutants from the combustion of alternative fuels: Phase 5/6 report  

SciTech Connect

As part of the US Department of Energy National Renewable Energy Laboratory program on alternative automotive fuels, the subcontractor has been conducting studies on the origin and fate of organic pollutants from the combustion of alternative fuels. Laboratory experiments were conducted simulating cold start of four alterative fuels (compressed natural gas, liquefied petroleum gas, methanol-gasoline mix, and ethanol-gasoline mix) using a commercial three-way catalyst under fuel-lean conditions. This report summarizes the results of these experiments. It appears that temperature of the catalyst is a more important parameter for fuel conversion and pollutant formation than oxygen concentration or fuel composition.

Sidhu, S.; Graham, J.; Taylor, P.; Dellinger, B. [Univ. of Dayton, OH (United States). Research Inst.

1998-05-01

198

Sensor for measuring the oxygen content in the exhaust gas of combustion engines and method thereof  

SciTech Connect

An improved lambda sensor is disclosed for the measurement of the oxygen content in the exhaust gas of internal combustion engines in which the sensor element is provided with a gas permeable wrapping coated with a catalyst. The sensor delivers a clear well defined signal in the so-called rich exhaust gas, which makes possible a more precise adjustment of the fuel-air mixture fed to the internal combustion engine.

Bozon, A.; Koberstein, E.; Pletka, H.; Voelker, H.

1982-12-07

199

Fuel injection system for internal combustion engine  

SciTech Connect

This patent describes a fuel injection system for an internal combustion engine provided with an intake passage, a cylinder associated with the intake passage and at least one intake valve associated with the cylinder, the fuel injection system including a fuel injector adapted to be disposed upstream of the intake valve. The fuel injector consists of: a housing, a hollow body connected to one end of the housing the hollow body having an end wall formed therein with an injection orifice; a valve member disposed slidably in the body comprising a needle valve of the type that is electromechanically operated; a pintle provided on the valve member for facilitating atomization of liquid fuel, the pintle extending outwardly from the hollow body through the injection orifice with a gap between an outer periphery of the pintle and an inner peripheral surface of the injection orifice to meter fuel to be injected; a sleeve member mounted on the hollow body to cover the injection orifice, the sleeve member defining therein a pintle-receiving space and a plurality of communication apertures adapted to communicate the pintle-receiving space with the intake passage of the engine, the total of the cross-sectional areas of the communication apertures being smaller than the cross-sectional area of the pintle-receiving space.

Kiuchi, H.; Ogawa, O.; Yamazoe, H.; Tasaka, H.; Kuroda, M.; Okino, S.

1988-09-27

200

Catalytic relight coating for gas turbine combustion chamber and method of application  

SciTech Connect

A gas turbine combustion chamber is described having a wall with an inner surface exposed to the combustion chamber flame, and a coating of a catalytic material on the surface over a large enough area thereof to cause reignition of the fuel-air mixture after flame-out.

Pfefferle, W.C.; Bak, M.J.

1986-08-05

201

NUMERICAL STUDY OF SPRAY PARAMETRIC EFFECTS ON GAS TURBINE COMBUSTION PERFORMANCE  

Microsoft Academic Search

A numerical study was conducted to determine the effects of fuel spray characteristics on the gas turbine combustion performance including the combustion efficiency and the overall temperature distribution factor (OTDF) at the exit of the combustor using the KIVA-3V code. A model of a typical annular combustor was used in the computations. Operating conditions were varied with inlet pressure from

K. Su; C. Q. Zhou

202

CO 2 processing and multi-pollutant control for oxy-fuel combustion systems using an advanced CO 2 capture and compression unit (CO 2CCU)  

Microsoft Academic Search

Oxy-fuel combustion of fossil fuels produces a CO2-rich gas stream with some impurities, such as nitrogen, argon, oxygen, nitrogen oxides, heavy metals and sulphur oxides, whose concentrations vary based on the type of fuel, combustion conditions, plant configuration, and other process related parameters. To control the greenhouse gas (GHG) emissions from these plants and sustain their operational competitiveness in a

Kourosh E. Zanganeh; Ahmed Shafeen; Carlos Salvador; Ashkan Beigzadeh; Maria Abbassi

2011-01-01

203

Hydrogen-fueled internal combustion engines.  

SciTech Connect

The threat posed by climate change and the striving for security of energy supply are issues high on the political agenda these days. Governments are putting strategic plans in motion to decrease primary energy use, take carbon out of fuels and facilitate modal shifts. Taking a prominent place in these strategic plans is hydrogen as a future energy carrier. A number of manufacturers are now leasing demonstration vehicles to consumers using hydrogen-fueled internal combustion engines (H{sub 2}ICEs) as well as fuel cell vehicles. Developing countries in particular are pushing for H{sub 2}ICEs (powering two- and three-wheelers as well as passenger cars and buses) to decrease local pollution at an affordable cost. This article offers a comprehensive overview of H{sub 2}ICEs. Topics that are discussed include fundamentals of the combustion of hydrogen, details on the different mixture formation strategies and their emissions characteristics, measures to convert existing vehicles, dedicated hydrogen engine features, a state of the art on increasing power output and efficiency while controlling emissions and modeling.

Verhelst, S.; Wallner, T.; Energy Systems; Ghent Univ.

2009-12-01

204

Advanced bioreactor concepts for gaseous substrates: Conversion of synthesis gas to liquid fuels and removal of SO{sub x} and NO{sub x} from coal combustion gases. CRADA final report  

SciTech Connect

The purpose of the proposed research program was the development and demonstration of a new generation of gaseous substrate-based bioreactors for the production of liquid fuels from coal synthesis gas and the removal of NO{sub x} and SO{sub x} species from coal combustion flue gas. This study addressed the further investigation of optimal bacterial strains, growth media and kinetics for the biocatalytic conversion of coal synthesis gas to liquid fuel such as ethanol and the reduction of gaseous flue gas constituents. The primary emphasis was on the development of advanced bioreactor systems coupled with innovative biocatalytic systems that will provide increased productivity under controlled conditions. It was hoped that this would result in bioprocessing options that have both technical and economic feasibility, thus, ensuring early industrial use. Predictive mathematical models were formulated to accommodate hydrodynamics, mass transport, and conversion kinetics, and provide the data base for design and scale-up. The program was separated into four tasks: (1) Optimization of Biocatalytic Kinetics; (2) Development of Well-mixed and Columnar Reactors; (3) Development of Predictive Mathematical Models; and (4) Industrial Demonstration. Research activities addressing both synthesis gas conversion and flue gas removal were conducted in parallel by BRI and ORNL respectively.

Kaufman, E.N.; Selvaraj, P.T.

1997-10-01

205

Cover and startup gas supply system for solid oxide fuel cell generator  

DOEpatents

A cover and startup gas supply system for a solid oxide fuel cell power generator is disclosed. Hydrocarbon fuel, such as natural gas or diesel fuel, and oxygen-containing gas are supplied to a burner. Combustion gas exiting the burner is cooled prior to delivery to the solid oxide fuel cell. The system mixes the combusted hydrocarbon fuel constituents with hydrogen which is preferably stored in solid form to obtain a non-explosive gas mixture. The system may be used to provide both non-explosive cover gas and hydrogen-rich startup gas to the fuel cell.

Singh, Prabhakar (Export, PA); George, Raymond A. (Pittsburgh, PA)

1999-01-01

206

Cover and startup gas supply system for solid oxide fuel cell generator  

DOEpatents

A cover and startup gas supply system for a solid oxide fuel cell power generator is disclosed. Hydrocarbon fuel, such as natural gas or diesel fuel, and oxygen-containing gas are supplied to a burner. Combustion gas exiting the burner is cooled prior to delivery to the solid oxide fuel cell. The system mixes the combusted hydrocarbon fuel constituents with hydrogen which is preferably stored in solid form to obtain a non-explosive gas mixture. The system may be used to provide both non-explosive cover gas and hydrogen-rich startup gas to the fuel cell. 4 figs.

Singh, P.; George, R.A.

1999-07-27

207

Heavy duty gas turbine combustion tests with simulated low BTU coal gas  

NASA Astrophysics Data System (ADS)

There is an increasing industry interest in integrated gas turbine combined cycle plants in which coal gasifiers provide the fuel for the gas turbines. Some gasifier plant designs, including the air-blown processes, some integrated oxygen blown processes and some oxygen-blown processes followed by heavy moisturization, produce fuel gases which have lower heating values ranging from 130 to below 100 BTU/scf for which there is little gas turbine combustion experience. This program has the objectives to: Parametrically determine the effects of moisture, nitrogen and carbon dioxide as diluents so that the combustion characteristics of many varieties of gasification product gases can be reasonably predicted without physically testing each specific gas composition; determine emissions characteristics including NO(x), CO, levels etc. associated with each of the diluents; operate with two syngas compositions; DOE chosen air-blown and integrated oxygen-blown, to confirm that the combustion characteristics are in line with predictions; determine if 'logical' refinements to the fuel nozzle will yield improved performance for LBTU fuels; determine the conversion rate of ammonia to NO(x); determine the effects of methane inclusion in the fuel.

Ekstrom, T. E.; Battista, R. A.; Maxwell, G. P.

208

Heavy duty gas turbine combustion tests with simulated low BTU coal gas  

SciTech Connect

There is an increasing industry interest in integrated gas turbine combined cycle plants in which coal gasifiers provide the fuel for the gas turbines. Some gasifier plant designs, including the air-blown processes, some integrated oxygen blown processes and some oxygen-blown processes followed by heavy moisturization, produce fuel gases which have lower heating values ranging from 130 to below 100 BTU/scf for which there is little gas turbine combustion experience. This program has the objectives to: Parametrically determine the effects of moisture, nitrogen and carbon dioxide as diluents so that the combustion characteristics of many varieties of gasification product gases can be reasonably predicted without physically testing each specific gas composition; determine emissions characteristics including NO{sub x}, CO, levels etc. associated with each of the diluents; operate with two syngas compositions; DOE chosen air-blown and integrated oxygen-blown, to confirm that the combustion characteristics are in line with predictions; determine if ``logical`` refinements to the fuel nozzle will yield improved performance for LBTU fuels; determine the conversion rate of ammonia to NO{sub x}; determine the effects of methane inclusion in the fuel.

Ekstrom, T.E.; Battista, R.A.; Maxwell, G.P.

1992-12-31

209

Heavy duty gas turbine combustion tests with simulated low BTU coal gas  

SciTech Connect

There is an increasing industry interest in integrated gas turbine combined cycle plants in which coal gasifiers provide the fuel for the gas turbines. Some gasifier plant designs, including the air-blown processes, some integrated oxygen blown processes and some oxygen-blown processes followed by heavy moisturization, produce fuel gases which have lower heating values ranging from 130 to below 100 BTU/scf for which there is little gas turbine combustion experience. This program has the objectives to: Parametrically determine the effects of moisture, nitrogen and carbon dioxide as diluents so that the combustion characteristics of many varieties of gasification product gases can be reasonably predicted without physically testing each specific gas composition; determine emissions characteristics including NO[sub x], CO, levels etc. associated with each of the diluents; operate with two syngas compositions; DOE chosen air-blown and integrated oxygen-blown, to confirm that the combustion characteristics are in line with predictions; determine if logical'' refinements to the fuel nozzle will yield improved performance for LBTU fuels; determine the conversion rate of ammonia to NO[sub x]; determine the effects of methane inclusion in the fuel.

Ekstrom, T.E.; Battista, R.A.; Maxwell, G.P.

1992-01-01

210

Synergistic combustion of coal with natural gas  

SciTech Connect

Engineers, using an improved coal devolatilization model and a simple char-burnout model, explored possible synergisms in the simultaneous combustion of coal and natural gas in boilers and kilns, for example. In the case of direct use of pulverized coal or of coal-water slurries with gas augmentation, the researchers identified those interactions in cofiring that speed up char burnout. In the second case - the two-stage use of pulverized coal or coal-water slurries with gas augmentation - they discovered that the primary role of the first stage is the methanogasification of coal analogous to, and possibly more effective than the hydrogasification of coal. In both instances, simultaneous coal/gas combustion appeared to be synergistic.

Green, A.E.S.; Pamidimukkala, K.M.

1984-01-01

211

Pressure-gain combustion for gas turbines  

SciTech Connect

As part of the Department of Energy`s Advanced Gas Turbine Systems Program, an investigation has been performed to evaluate {open_quotes}pressure-gain{close_quotes} combustion systems for gas turbine applications. Results from the investigation have shown that, due to the oscillatory combustion process, a pressure boost can be achieved for suitable combustor geometries. The pressure gains achieved thus far have been as high as 1 percent. It has also been shown that for some combustor designs operating under typical gas turbine conditions, NO{sub x} and CO emissions are about 30 ppmv and 8 ppmv, respectively. It is believed that with optimized designs, further improvements in both pressure gain and emissions may be possible. We have concluded that this technology remains a candidate for improving the efficiency of a gas turbine while reducing pollutant emissions.

Gemmen, R.; Richards, G.; Janus, M.

1995-12-01

212

Combustion Light Gas Gun Technology Demonstration.  

National Technical Information Service (NTIS)

The Combustion Light Gas Gun, or CLGG, has been investigated for over ten years. During this time, the research has shown that the technology provides a minimum of 30% more muzzle energy than advanced solid propellent guns which translates to significant ...

D. Kruczynski D. Massey R. Milligan E. Vigil B. Landers

2007-01-01

213

Synthetic fuel aromaticity and staged combustion  

SciTech Connect

Samples of middle and heavy SRC-II distillates were distilled into 50 C boiling point range fractions. These were characterized by measurements of their molecular weight, elemental analysis and basic nitrogen content and calculation of average molecular structures. The structures typically consisted of 1 to 3 aromatic rings fused to alicyclic rings with short, 1 to 3 carbon aliphatic side chains. The lower boiling fractions contained significant amounts (1 atom/molecule) of oxygen while the heavier fractions contained so few heteroatoms that they were essentially hydrocarbons. Laboratory scale oxidative-pyrolysis experiments were carried out at pyrolysis temperatures of 500 to 1100 C and oxygen concentrations from 0 to 100 percent of stoichiometry. Analysis of liquid products, collected in condensers cooled with liquid nitrogen showed that aromatization is a major reaction in the absence of oxygen. The oxygen-containing materials (phenolics) seem to be more resistant to thermal pyrolysis than unsubstituted aromatics. Nitrogen converts from basic to nonbasic forms at about 500 C. The nonbasic nitrogen is more stable and survives up to 700 C after which it is slowly removed. A recently constructed 50,000 Btu/hr staged combustor was used to study the chemistry of the nitrogen and aromatics. SRC II combustion was studied under fuel-rich, first-stage conditions at air/fuel ratios from 0.6 to 1.0 times stoichiometric. The chemistry of the fuel during combustion calls for further investigation in order to examine the mechanism by which HCN is evolved as a common intermediate for the formation of the nitrogen-containing gaseous combustion products. 25 references, 45 figures, 25 tables.

Longanbach, J. R.; Chan, L. K.; Levy, A.

1982-11-15

214

Analysis of Fuel Vaporization, Fuel-Air Mixing, and Combustion in Integrated Mixer-Flame Holders  

NASA Technical Reports Server (NTRS)

Requirements to limit pollutant emissions from the gas turbine engines for the future High-Speed Civil Transport (HSCT) have led to consideration of various low-emission combustor concepts. One such concept is the Integrated Mixer-Flame Holder (IMFH). This report describes a series of IMFH analyses performed with KIVA-II, a multi-dimensional CFD code for problems involving sprays, turbulence, and combustion. To meet the needs of this study, KIVA-II's boundary condition and chemistry treatments are modified. The study itself examines the relationships between fuel vaporization, fuel-air mixing, and combustion. Parameters being considered include: mixer tube diameter, mixer tube length, mixer tube geometry (converging-diverging versus straight walls), air inlet velocity, air inlet swirl angle, secondary air injection (dilution holes), fuel injection velocity, fuel injection angle, number of fuel injection ports, fuel spray cone angle, and fuel droplet size. Cases are run with and without combustion to examine the variations in fuel-air mixing and potential for flashback due to the above parameters. The degree of fuel-air mixing is judged by comparing average, minimum, and maximum fuel/air ratios at the exit of the mixer tube, while flame stability is monitored by following the location of the flame front as the solution progresses from ignition to steady state. Results indicate that fuel-air mixing can be enhanced by a variety of means, the best being a combination of air inlet swirl and a converging-diverging mixer tube geometry. With the IMFH configuration utilized in the present study, flashback becomes more common as the mixer tube diameter is increased and is instigated by disturbances associated with the dilution hole flow.

Deur, J. M.; Cline, M. C.

2004-01-01

215

Combustion and emissions characteristics of a compression-ignition engine using dual ammonia-diesel fuel  

Microsoft Academic Search

This study investigated the performance of a compression-ignition engine using a dual-fuel approach with ammonia and diesel fuel. With the world's increasing need for alternative energy and clean emissions, ammonia stands out as a viable candidate since its combustion does not produce the known greenhouse gas, carbon dioxide. Ammonia is one of the world's most synthesized chemicals and its infrastructure

Aaron Reiter

2009-01-01

216

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

217

Apparatus and method for operating internal combustion engines from variable mixtures of gaseous fuels  

DOEpatents

An apparatus and method for utilizing any arbitrary mixture ratio of multiple fuel gases having differing combustion characteristics, such as natural gas and hydrogen gas, within an internal combustion engine. The gaseous fuel composition ratio is first sensed, such as by thermal conductivity, infrared signature, sound propagation speed, or equivalent mixture differentiation mechanisms and combinations thereof which are utilized as input(s) to a "multiple map" engine control module which modulates selected operating parameters of the engine, such as fuel injection and ignition timing, in response to the proportions of fuel gases available so that the engine operates correctly and at high efficiency irrespective of the gas mixture ratio being utilized. As a result, an engine configured according to the teachings of the present invention may be fueled from at least two different fuel sources without admixing constraints.

Heffel, James W. (Lake Matthews, CA); Scott, Paul B. (Northridge, CA); Park, Chan Seung (Yorba Linda, CA)

2011-11-01

218

Combustion Characteristics of Liquid Normal Alkane Fuels in a Model Combustor of Supersonic Combustion Ramjet Engine  

NASA Astrophysics Data System (ADS)

Effect of kinds of one-component n-alkane liquid fuels on combustion characteristics was investigated experimentally using a model combustor of scramjet engine. The inlet condition of a model combustor is 2.0 of Mach number, up to 2400K of total temperature, and 0.38MPa of total pressure. Five kinds of n-alkane are tested, of which carbon numbers are 7, 8, 10, 13, and 16. They are more chemically active and less volatile with an increase of alkane carbon number. Fuels are injected to the combustor in the upstream of cavity with barbotage nitrogen gas and self-ignition performance was investigated. The result shows that self-ignition occurs with less equivalence ratio when alkane carbon number is smaller. This indicates that physical characteristic of fuel, namely volatile of fuel, is dominant for self-ignition behavior. Effect on flame-holding performance is also examined with adding pilot hydrogen and combustion is kept after cutting off pilot hydrogen with the least equivalence ratio where alkane carbon number is from 8 to 10. These points are discussed qualitatively from the conflict effect of chemical and physical properties on alkane carbon number.

??, ?; ??, ??; ??, ??; ??, ???; ??, ??; ??, ??; ??, ??

219

Combustion and fuel characterization of coal-water fuels  

SciTech Connect

Activities conducted under this contract include studies on the combustion and fireside behavior of numerous coal-water fuels (CWFs). The work has been broken down into the following areas: Task 1 -- Selection of Candidate Fuels; Task 2 -- Bench Scale Tests; Task 3 -- CWF Preparation and Supply; Task 4 -- Combustion Characterization; Task 5 -- Ash Deposition and Performance Testing; Task 6 -- Commercial Applications. This report covers Task 6, the study of commercial applications of CWFs as related to the technical and economic aspects of the conversion of existing boilers and heaters to CWF firing. This work involves the analysis of seven units of various sizes and configurations firing several selected CWFs. Three utility boilers, two industrial boilers, and two process heater designs are included. Each of the units was considered with four primary selected CWFs. A fifth fuel was considered for one of the utility units. A sixth fuel, a microfine grind CWF, was evaluated on two utility units and one industrial unit. The particular fuels were chosen with the objective of examining the effects of coal source, ash level, ash properties, and beneficiation on the CWF performance and economics of the seven units. 10 refs., 81 figs., 80 tabs.

Beal, H.R.; Gralton, G.W.; Gronauer, T.W.; Liljedahl, G.N.; Love, B.F.

1987-06-01

220

Combustion Sensors: Gas Turbine Applications.  

National Technical Information Service (NTIS)

This report documents efforts to survey the current research directions in sensor technology for gas turbine systems. The work is driven by the current and future requirements on system performance and optimization. Accurate real time measurements of velo...

M. Human

2002-01-01

221

Assessment of organic contaminants in emissions from refuse-derived fuel combustion  

SciTech Connect

Organic contaminants in emissions from refuse-derived fuel combustion were investigated in a 20-inch-diameter atmospheric fluidized-bed combustor. Combinations of coal/EcoFuel/MSW/toluene were burned inthe combustor with temperatures ranging from 1250 to 1550 degrees F. A Source Assessment Sampling System (SASS) was used to sample the stack gas; Level 1 methodology was used to analyze the organic-contaminant levels. Combustion efficiencies of 93 to 98 percent were achieved in the test burns. Combustion of the EcoFuel generated fewer organic emissions than combustion of coal at similar combustion temperatures. The fine particulate collected by the SASS train filter contained higher concentrations of extractable organics than the reactor fly ash and the SASS cyclone samples. Combustion of a toluene/EcoFuel mix generated a large number of benzene derivatives not seen in the combustion of pure EcoFuel. Polycyclic aromatic hydrocarbons were the dominant organic compounds contained in the XAD-2 resin extract from coal combustion. A number of different priority pollutants were identified in the samples collected.

Chrostowski, J.; Wait, D.; Kwong, E.; Jefferies, A.; Rodgers, C.

1985-09-01

222

Detailed chemical kinetic mechanisms for combustion of oxygenated fuels  

Microsoft Academic Search

Thermodynamic properties and detailed chemical kinetic models have been developed for the combustion of two oxygenates: methyl butanoate, a model compound for biodiesel fuels, and methyl formate, a related simpler molecule. Bond additivity methods and rules for estimating kinetic parameters were adopted from hydrocarbon combustion and extended. The resulting mechanisms have been tested against the limited combustion data available in

E. M. Fisher; W. J. Pitz; H. J. Curran; C. K. Westbrook

2000-01-01

223

Axially staged combustion system for a gas turbine engine  

DOEpatents

An axially staged combustion system is provided for a gas turbine engine comprising a main body structure having a plurality of first and second injectors. First structure provides fuel to at least one of the first injectors. The fuel provided to the one first injector is adapted to mix with air and ignite to produce a flame such that the flame associated with the one first injector defines a flame front having an average length when measured from a reference surface of the main body structure. Each of the second injectors comprising a section extending from the reference surface of the main body structure through the flame front and having a length greater than the average length of the flame front. Second structure provides fuel to at least one of the second injectors. The fuel passes through the one second injector and exits the one second injector at a location axially spaced from the flame front.

Bland, Robert J. (Oviedo, FL)

2009-12-15

224

Self-oscillations of an unstable fuel combustion in the combustion chamber of a liquid-propellant rocket engine  

NASA Astrophysics Data System (ADS)

The form of the self-oscillations of a vibrating combustion of a fuel in the combustion chamber of a liquidpropellant rocket engine, caused by the fuel-combustion lag and the heat release, was determined. The character of change in these self-oscillations with increase in the time of the fuel-combustion lag was investigated.

Gotsulenko, V. V.; Gotsulenko, V. N.

2013-01-01

225

Carbonation of fly ash in oxy-fuel CFB combustion  

Microsoft Academic Search

Oxy-fuel combustion of fossil fuel is one of the most promising methods to produce a stream of concentrated CO2 ready for sequestration. Oxy-fuel FBC (fluidized bed combustion) can use limestone as a sorbent for in situ capture of sulphur dioxide. Limestone will not calcine to CaO under typical oxy-fuel circulating FBC (CFBC) operating temperatures because of the high CO2 partial

Chunbo Wang; Lufei Jia; Yewen Tan; E. J. Anthony

2008-01-01

226

Proceedings of the 1996 international joint power generation conference -- Volume 1: Environmental control\\/fuels and combustion technologies. EC-Volume 4; FACT-Volume 21  

Microsoft Academic Search

This book contains the proceedings of the 1996 International Joint Power Generation Conference, Volume 1, Environmental Control\\/Fuels and Combustion Technologies. The topics of the papers NO emissions control using evaluation and design, NO emissions control using boiler tuning and modifications, gas turbine combustion, contribution of combustion modeling to NO reduction, experience in retrofitting NO combustion technology to utility boilers, power

S. M. Smouse; A. Gupta

1996-01-01

227

Fossil Fuel Combustion and the Major Sedimentary Cycle  

Microsoft Academic Search

The combustion of the fossil fuels coal, oil, and lignite potentially can mobilize many elements into the atmosphere at rates, in general, less than but comparable to their rates of flow through natural waters during the weathering cycle. Since the principal sites of fossil fuel combustion are in the mid-latitudes of the Northern Hemisphere, changes in the composition of natural

K. K. Bertine; Edward D. Goldberg

1971-01-01

228

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

229

Oxy-combustion of high water content fuels  

NASA Astrophysics Data System (ADS)

As the issues of global warming and the energy crisis arouse extensive concern, more and more research is focused on maximizing energy efficiency and capturing CO2 in power generation. To achieve this, in this research, we propose an unconventional concept of combustion - direct combustion of high water content fuels. Due to the high water content in the fuels, they may not burn under air-fired conditions. Therefore, oxy-combustion is applied. Three applications of this concept in power generation are proposed - direct steam generation for the turbine cycle, staged oxy-combustion with zero flue gas recycle, and oxy-combustion in a low speed diesel-type engine. The proposed processes could provide alternative approaches to directly utilize fuels which intrinsically have high water content. A large amount of energy to remove the water, when the fuels are utilized in a conventional approach, is saved. The properties and difficulty in dewatering high water content fuels (e.g. bioethanol, microalgae and fine coal) are summarized. These fuels include both renewable and fossil fuels. In addition, the technique can also allow for low-cost carbon capture due to oxy-combustion. When renewable fuel is utilized, the whole process can be carbon negative. To validate and evaluate this concept, the research focused on the investigation of the flame stability and characteristics for high water content fuels. My study has demonstrated the feasibility of burning fuels that have been heavily diluted with water in a swirl-stabilized burner. Ethanol and 1-propanol were first tested as the fuels and the flame stability maps were obtained. Flame stability, as characterized by the blow-off limit -- the lowest O2 concentration when a flame could exist under a given oxidizer flow rate, was determined as a function of total oxidizer flow rate, fuel concentration and nozzle type. Furthermore, both the gas temperature contour and the overall ethanol concentration in the droplets along the spray were measured in the chamber for a stable flame. The experimental results indicate significant preferential vaporization of ethanol over water. Modeling results support this observation and indicate that the vaporization process is best described as the distillation limit mode with enhanced mass transfer by convection. Further, the influence of preferential vaporization on flame stability was investigated. A procedure was developed to evaluate the extent of preferential vaporization and subsequent flame stability of a fuel in aqueous solution. Various water soluble fuels were analyzed via this procedure in order to identify a chemical fuel showing strong preferential vaporization. t-Butanol was identified as having excellent physical and chemical properties, indicating stronger preferential vaporization than ethanol. Flame stability tests were run for aqueous solutions of both t-butanol and ethanol under identical flow conditions. Flame stability was characterized by the blow-off limit. In each comparison, the energy contents in the two solutions were kept the same. For the experiments under high swirl flow conditions (100% swirl flow), 12.5 wt% t-butanol has slightly lower blow-off limits than 15 wt% ethanol, and 8.3 wt% t-butanol has much lower blow-off limits than 10 wt% ethanol. For the experiments under a low swirl flow condition (50% swirl/50% axial flow), 12.5 wt% t-butanol has a much lower blow-off limit than 15 wt% ethanol. The time to release the fuel from a droplet was also calculated for both ethanol and t-butanol. For the same size droplet, the time to release t-butanol is much shorter than that of ethanol under the same conditions. Faster release of the fuel from water enhances flame stability, which is consistent with the experimental results. For the oxy-combustion characteristics of low-volatility fuel with high water content, glycerol was chosen as the fuel to study. It is found that self-sustained flame can be obtained for glycerol solution with concentration as high as 60 wt%, when burned in pure O2. However, the flame is lifted far away f

Yi, Fei

230

Fuel reforming apparatus for use with internal combustion engine  

Microsoft Academic Search

The invention discloses a fuel reforming apparatus for use with an internal combustion engine, comprising hydrocarbon fuel supply means for producing a mixture of hydrocarbon fuel with air in a suitable air-fuel ratio, a burning chamber in which the mixture is ignited and burned, and a reactor which is packed with a catalyst adapted to carry out the catalytic reforming,

M. Noguchi; T. Bunda; T. Tanaka

1978-01-01

231

Advanced coal-fueled gas turbine systems  

SciTech Connect

Several technology advances since the early coal-fueled turbine programs that address technical issues of coal as a turbine fuel have been developed in the early 1980s: Coal-water suspensions as fuel form, improved methods for removing ash and contaminants from coal, staged combustion for reducing NO{sub x} emissions from fuel-bound nitrogen, and greater understanding of deposition/erosion/corrosion and their control. Several Advanced Coal-Fueled Gas Turbine Systems programs were awarded to gas turbine manufacturers for for components development and proof of concept tests; one of these was Allison. Tests were conducted in a subscale coal combustion facility and a full-scale facility operating a coal combustor sized to the Allison Model 501-K industrial turbine. A rich-quench-lean (RQL), low nitrogen oxide combustor design incorporating hot gas cleanup was developed for coal fuels; this should also be applicable to biomass, etc. The combustor tests showed NO{sub x} and CO emissions {le} levels for turbines operating with natural gas. Water washing of vanes from the turbine removed the deposits. Systems and economic evaluations identified two possible applications for RQL turbines: Cogeneration plants based on Allison 501-K turbine (output 3.7 MW(e), 23,000 lbs/hr steam) and combined cycle power plants based on 50 MW or larger gas turbines. Coal-fueled cogeneration plant configurations were defined and evaluated for site specific factors. A coal-fueled turbine combined cycle plant design was identified which is simple, compact, and results in lower capital cost, with comparable efficiency and low emissions relative to other coal technologies (gasification, advanced PFBC).

Wenglarz, R.A.

1994-08-01

232

Trace gas emissions from combustion of peat, crop residue, biofuels, grasses, and other fuels: configuration and FTIR component of the fourth Fire Lab at Missoula Experiment (FLAME-4)  

NASA Astrophysics Data System (ADS)

During the fourth Fire Lab at Missoula Experiment (FLAME-4, October-November~2012) a~large variety of regionally and globally significant biomass fuels was burned at the US Forest Service Fire Sciences Laboratory in Missoula, Montana. The particle emissions were characterized by an extensive suite of instrumentation that measured aerosol chemistry, size distribution, optical properties, and cloud-nucleating properties. The trace gas measurements included high resolution mass spectrometry, one- and two-dimensional gas chromatography, and open-path Fourier transform infrared (OP-FTIR) spectroscopy. This paper summarizes the overall experimental design for FLAME-4 including the fuel properties, the nature of the burn simulations, the instrumentation employed, and then focuses on the OP-FTIR results. The OP-FTIR was used to measure the initial emissions of 20 trace gases: CO2, CO, CH4, C2H2, C2H4, C3H6, HCHO, HCOOH, CH3OH, CH3COOH, glycolaldehyde, furan, H2O, NO, NO2, HONO, NH3, HCN, HCl, and SO2. These species include most of the major trace gases emitted by biomass burning and for several of these compounds it is the first time their emissions are reported for important fuel types. The main fuel types included: African grasses, Asian rice straw, cooking fires (open (3-stone), rocket, and gasifier stoves), Indonesian and extratropical peat, temperate and boreal coniferous canopy fuels, US crop residue, shredded tires, and trash. Comparisons of the OP-FTIR emission factors (EF) and emission ratios (ER) to field measurements of biomass burning verify that the large body of FLAME-4 results can be used to enhance the understanding of global biomass burning and its representation in atmospheric chemistry models.

Stockwell, C. E.; Yokelson, R. J.; Kreidenweis, S. M.; Robinson, A. L.; DeMott, P. J.; Sullivan, R. C.; Reardon, J.; Ryan, K. C.; Griffith, D. W. T.; Stevens, L.

2014-04-01

233

Detailed Chemical Kinetic Modeling of Diesel Combustion with Oxygenated Fuels  

SciTech Connect

Emission standards for diesel engines in vehicles have been steadily reduced in recent years, and a great deal of research and development effort has been focused on reducing particulate and nitrogen oxide emissions. One promising approach to reducing emissions involves the addition of oxygen to the fuel, generally by adding an oxygenated compound to the normal diesel fuel. Miyamoto et al. [1] showed experimentally that particulate levels can be significantly reduced by adding oxygenated species to the fuel. They found the Bosch smoke number (a measure of the particulate or soot levels in diesel exhaust) falls from about 55% for conventional diesel fuel to less than 1% when the oxygen content of the fuel is above about 25% by mass, as shown in Figure 1. It has been well established that addition of oxygenates to automotive fuel, including both diesel fuel as well as gasoline, reduces NOx and CO emissions by reducing flame temperatures. This is the basis for addition of oxygenates to produce reformulated gasoline in selected portions of the country. Of course, this is also accompanied by a slight reduction in fuel economy. A new overall picture of diesel combustion has been developed by Dec [2], in which laser diagnostic studies identified stages in diesel combustion that had not previously been recognized. These stages are summarized in Figure 2. The evolution of the diesel spray is shown, starting as a liquid jet that vaporizes and entrains hot air from the combustion chamber. This relatively steady process continues as long as fuel is being injected. In particular, Dec showed that the fuel spray vaporizes and mixes with air and products of earlier combustion to provide a region in which a gas phase, premixed fuel-rich ignition and burn occurs. The products of this ignition are then observed experimentally to lead rapidly to formation of soot particles, which subsequently are consumed in a diffusion flame. Recently, Flynn et al. [3] used a chemical kinetic and mixing model to study the premixed, rich ignition process. Using n-heptane as a representative diesel fuel, they showed that addition of an oxygenated additive, methanol, to the fuel reduced the concentrations of a number of hydrocarbon species in the products of the rich ignition. Specifically, methanol addition reduced the total concentrations of acetylene, ethylene and 1,3-butadiene, as well as propargyl and vinyl radicals, in the ignition products. These are the same species shown in a number of studies [4-6] to be responsible for formation of aromatic and polycyclic aromatic species in flames, species which lead eventually to production of soot. Flynn et al. did not, however, examine the kinetic processes responsible for the computed reduction in production of soot precursor species. At least two hypotheses have been advanced to explain the role that oxygenated species play in diesel ignition and the reduction in the concentrations of these species. The first is that the additive, methanol in the case of Flynn et al., does not contain any C-C bonds and cannot then produce significant levels of the species such as acetylene, ethylene or the unsaturated radicals which are known to lead to aromatic species. The second hypothesis is that the product distribution changes very naturally as oxygen is added and the overall equivalence ratio is reduced. In the present study, we repeat the ignition calculations of Flynn et al. and include a number of other oxygenated species to determine which of these theories is more applicable to this model.

Curran, H J; Fisher, E M; Glaude, P-A; Marinov, N M; Pitz, W J; Westbrook, C K; Flynn, P F; Durrett, R P; zur Loye, A O; Akinyemi, O C; Dryer, F L

2000-01-11

234

Fuel/oxidizer-rich high-pressure preburners. [staged-combustion rocket engine  

NASA Technical Reports Server (NTRS)

The analyses, designs, fabrication, and cold-flow acceptance testing of LOX/RP-1 preburner components required for a high-pressure staged-combustion rocket engine are discussed. Separate designs of injectors, combustion chambers, turbine simulators, and hot-gas mixing devices are provided for fuel-rich and oxidizer-rich operation. The fuel-rich design addresses the problem of non-equilibrium LOX/RP-1 combustion. The development and use of a pseudo-kinetic combustion model for predicting operating efficiency, physical properties of the combustion products, and the potential for generating solid carbon is presented. The oxygen-rich design addresses the design criteria for the prevention of metal ignition. This is accomplished by the selection of materials and the generation of well-mixed gases. The combining of unique propellant injector element designs with secondary mixing devices is predicted to be the best approach.

Schoenman, L.

1981-01-01

235

[Combustion gas toxicity of textiles (author's transl)].  

PubMed

Textiles are used so widely as interior materials of many buildings, houses, and transportation facilities, that the combustion gas has a chance of intoxication of a fire accident. Therefore this investigation was undertaken to clarify the toxicity of the gas and to obtain an index for safety standards in such cases. The combustion gases of cotton, polypropylene, acrylic, flame retardant (F.R.) cotton and F.R. acrylic fabrics were analyzed by a gas chromatograph and a GC-Mass spectorograph, and also tested with experimental animals to determine the lethal factors including blood gas analyzing technique. The gas exposuring test based on gas analysis data showed that the toxicity of these combustion products increased in the following orders: cotton, polypropylene, F.R. cotton, F.R. acrylic and acrylic. Comparative indices of the toxicity showed that acrylic increased 7.26-fold as compared with that of cotton. It was recognized that the lethal factors in the mice was due to carbon monoxide and/or hydrogen cyanide during the exposure one hour, and that sequelae due to acrolein during the seven day observation period after the exposure. Flame retardant treatment increased twice the toxicity of cotton. On the contrary, that of acrylic was reduced by 0.8 time compared with the original fabric, so that the treatment could be recommended only in case of acrylic from the safety standpoint. From the above results, it can be stressed that vigorous smoke exhaust procedure should be executed in the case of fire accidents for saving human lives. PMID:470212

Iwasaki, K

1979-01-01

236

LIEKKI and JALO: Combustion and fuel conversion  

NASA Astrophysics Data System (ADS)

LIEKKI and JALO are well conceived and structured programs designed to strengthen Finland's special needs in combustion and gasification to utilize a diversity of fuels, increase the ratio of electrical to heat output, and to support the export market. Started in 1988, these two programs provide models of how universities, Technical research center's laboratories (VTT's), and industry can collaborate successfully in order to achieve national goals. The research is focused on long term goals in certain targeted niche areas. This is an effective way to use limited resources. The niche areas were chosen in a rational manner and appear to be appropriate for Finland. The LIEKKl and JALO programs have helped pull together research efforts that were previously more fragmented. For example, the combustion modeling area still appears fragmented. Individual project objectives should be tied to program goals at a very early stage to provide sharper focusing to the research. Both the LIEKKl and JALO programs appear to be strongly endorsed by industry. Industrial members of the Executive Committees were very supportive of these programs. There are good mechanisms for technology transfer in place, and the programs provide opportunities to establish good interfaces between industrial people and the individual researchers. The interest of industry is shown by the large number of applied projects that are supported by industry. This demonstrates the relevancy of the programs. There is a strong interaction between the JALO program and industry in black liquor gasification.

Grace, Thomas M.; Renz, Ulrich; Sarofim, Adel F.

237

Pressure-controlled fuel injection for internal combustion engines  

SciTech Connect

This patent describes a method of injecting fuel into a combustion chamber of an internal combustion engine, comprising the steps of: (a) selecting an accumulator type fuel injector having a fuel input, and characterized by the fact that the withdrawal of applied pressure from its input initiates the injection of a fuel charge; (b) placing the fuel injector in operative relation to the combustion chamber; (c) selecting an electronically controlled three-way valve for selectively admitting fuel into the accumulator type fuel injector; (d) coupling the valve to the injector; (e) coupling a source of liquid diesel fuel to the valve; and (f) whenever it is desired to inject a fuel charge into the combustion chamber, applying an electronic control signal to the valve to open the valve for a selected period of time, whereby at the end of the selected period of time when the valve closes to pressure and opens to vent, the accumulation type injector causes the injection of the fuel charge into the combustion chamber to be initiated. The termination of injection of the fuel charge is controlled by the accumulator type fuel injector and not by the valve or the electronic control signal.

Beck, N.J.; Calkins, M.A.; Weseloh, W.E.; Barkhimer, R.L.

1986-12-16

238

Adaptation of Combustion Principles to Aircraft Propulsion. Volume I; Basic Considerations in the Combustion of Hydrocarbon Fuels with Air  

NASA Technical Reports Server (NTRS)

The report summarizes source material on combustion for flight-propulsion engineers. First, several chapters review fundamental processes such as fuel-air mixture preparation, gas flow and mixing, flammability and ignition, flame propagation in both homogenous and heterogenous media, flame stabilization, combustion oscillations, and smoke and carbon formation. The practical significance and the relation of these processes to theory are presented. A second series of chapters describes the observed performance and design problems of engine combustors of the principal types. An attempt is made to interpret performance in terms of the fundamental processes and theories previously reviewed. Third, the design of high-speed combustion systems is discussed. Combustor design principles that can be established from basic considerations and from experience with actual combustors are described. Finally, future requirements for aircraft engine combustion systems are examined.

Barnett, Henry C (Editor); Hibbard, Robert R (Editor)

1955-01-01

239

Development of combustion data to utilize low-Btu gases as industrial process fuels. Project 8985 special report No. 2, Kiln Burner. [From natural gas to low Btu gas  

Microsoft Academic Search

Data were gathered to determine the performance of a kiln burner when retrofit with three low-Btu gases. The burner was fired on the IGT pilot-scale test furnaces with a load simulating the calcining and reaction zones of a cement kiln. The low- and medium-Btu gases simulated for these combustion trials were Koppers-Totzek oxygen, Wellman-Galusha air, and Winkler air fuel gases.

R. T. Waibel; E. S. Fleming

1978-01-01

240

Exhaust gas purifying system for internal combustion engine  

SciTech Connect

An exhaust gas purifying system for an automobile engine including at least first and second engine cylinder has a shutter valve for interrupting the supply of a combustible air-fuel mixture to the first engine cylinder during a particular engine operating condition, a three-way electromagnetically operated valve for controlling the operation of the shutter valve, and a secondary air supply unit including a switching valve for selectively supplying a secondary air to a portion of an exhaust passage upstream of at least one catalyst unit disposed in the exhaust passage.

Higashi, H.; Iida, K.; Shiraishi, H.

1982-08-24

241

A test device for premixed gas turbine combustion oscillations  

SciTech Connect

This paper discusses the design and operation of a test combustor suitable for studying combustion oscillations caused by a commercial-scale gas turbine fuel nozzle. Aside from the need to be conducted at elevated pressures and temperatures, it is desirable for the experimental device to be flexible in its geometry so as to provide an acoustic environment representative of the commercial device. The combustor design, capabilities, and relevant instrumentation for such a device are presented, along with initial operating experience and preliminary data that suggests the importance of nozzle reference velocity and air temperature.

Richards, G.A.; Gemmen, R.S.; Yip, M.J.

1996-09-01

242

Characteristics and combustion of future hydrocarbon fuels. [aircraft fuels  

NASA Technical Reports Server (NTRS)

As the world supply of petroleum crude oil is being depleted, the supply of high-quality crude oil is also dwindling. This dwindling supply is beginning to manifest itself in the form of crude oils containing higher percentages of aromatic compounds, sulphur, nitrogen, and trace constituents. The result of this trend is described and the change in important crude oil characteristics, as related to aircraft fuels, is discussed. As available petroleum is further depleted, the use of synthetic crude oils (those derived from coal and oil shale) may be required. The principal properties of these syncrudes and the fuels that can be derived from them are described. In addition to the changes in the supply of crude oil, increasing competition for middle-distillate fuels may require that specifications be broadened in future fuels. The impact that the resultant potential changes in fuel properties may have on combustion and thermal stability characteristics is illustrated and discussed in terms of ignition, soot formation, carbon deposition flame radiation, and emissions.

Rudey, R. A.; Grobman, J. S.

1978-01-01

243

Development of colorless distributed combustion for gas turbine application  

NASA Astrophysics Data System (ADS)

Colorless Distributed Combustion (CDC) is investigated for gas turbine engine application due to its benefit for ultra-low pollutant emission, improved pattern factor, low noise emission, stable combustion and low pressure drop, alleviation of combustion instabilities and increased life of turbine blades with less air cooling requirements. The CDC is characterized by discrete and direct injection of fuel and air at high velocity and the reaction zone is stabilized due to controlled aerodynamics inside the combustor and wider (radially) shear layer mixing. Mixing between the injected air and product gases to form hot and diluted oxidant is required followed by rapid mixing with the fuel. This results in distributed reaction zone instead of a concentrated flame front as observed in conventional diffusion flames and hence, to avoid hot spot regions and provide reduced NOx and CO emissions. The focus of this dissertation is to develop and demonstrate CDC for application to stationary gas turbine combustors which generally operate at thermal intensity of 15MW/m3-atm. However, higher thermal intensity is desirable to reduce hardware costs due to smaller weight and volume of the combustors. Design of high thermal intensity CDC combustor requires careful control of critical parameters, such as, gas recirculation, fuel/oxidizer mixing and residence time characteristics via careful selection of different air and fuel injection configurations to achieve desirable combustion characteristics. This dissertation examines sequential development of low emission colorless distributed combustor operating from thermal intensity of 5MW/m3-atm up to 198MW/m3-atm. Initially, various fuel and air injection configurations were investigated at a low thermal intensity of 5MW/m 3-atm. Further investigations were performed for a simpler combustor having single air and fuel injection ports for medium thermal intensity range of 28-57MW/m3-atm. Among the flow configurations investigated, reverse cross-flow configuration was found to give more favorable results possibly due to higher residence time because of reverse flow geometry and faster mixing with the fuel injection in cross-flow. This configuration was investigated in detail by further reducing the combustor volume to give ultra-high thermal intensity of up to 198MW/m3-atm. At thermal intensity of 53MW/m3-atm NO emissions were 4ppm in non-premixed mode and 1ppm in premixed mode and CO emissions were 30ppm in both the modes. The pressure loss was less than 5% and heat loss was less than 15%. The pressure fluctuations were less than 0.025% suggesting very stable combustion. At ultra-high thermal intensity of 170MW/m3-atm NO emissions were 8ppm and 3ppm in non-premixed and premixed modes respectively and CO emissions were about 100ppm in both the modes. Dilution of fuel with nitrogen, carbon dioxide and air resulted in significant reduction in NO emission in non-premixed mode from 8ppm to about 2ppm. Methane was used as fuel for all these investigations. Liquid fuel (ethanol) was also tested and very low NO emission of about 6ppm was obtained in direct injection mode and 2ppm in premixed prevaporized mode. CO emission of about 200ppm was observed in both the modes.

Arghode, Vaibhav Kumar

244

Quantitative measurements of in-cylinder gas composition in a controlled auto-ignition combustion engine  

NASA Astrophysics Data System (ADS)

One of the most effective means to achieve controlled auto-ignition (CAI) combustion in a gasoline engine is by the residual gas trapping method. The amount of residual gas and mixture composition have significant effects on the subsequent combustion process and engine emissions. In order to obtain quantitative measurements of in-cylinder residual gas concentration and air/fuel ratio, a spontaneous Raman scattering (SRS) system has been developed recently. The optimized optical SRS setups are presented and discussed. The temperature effect on the SRS measurement is considered and a method has been developed to correct for the overestimated values due to the temperature effect. Simultaneous measurements of O2, H2O, CO2 and fuel were obtained throughout the intake, compression, combustion and expansion strokes. It shows that the SRS can provide valuable data on this process in a CAI combustion engine.

Zhao, H.; Zhang, S.

2008-01-01

245

High-temperature reduction of nitrogen oxides in oxy-fuel combustion  

Microsoft Academic Search

The possibility of high-temperature reduction of nitrogen oxides (NOx) in oxy-fuel combustion is investigated. A detailed gas-phase model identifies the effect of temperature, stoichiometric ratio, residence time and composition of the oxidizer on NOx reduction. It is concluded that an efficient high-temperature reduction of NOx is achieved with high-purity oxygen, negligible amount of air ingress, presence of a sub-stoichiometric combustion

Fredrik Normann; Klas Andersson; Bo Leckner; Filip Johnsson

2008-01-01

246

The Impact of Alternative Fuels on Combustion Kinetics  

SciTech Connect

The research targets the development of detailed kinetic models to quantitatively characterize the impact of alternative fuels on the performance of Navy turbines and diesel engines. Such impacts include kinetic properties such as cetane number, flame speed, and emissions as well as physical properties such as the impact of boiling point distributions on fuel vaporization and mixing. The primary focus will be Fischer-Tropsch liquids made from natural gas, coal or biomass. The models will include both the effects of operation with these alternative fuels as well as blends of these fuels with conventional petroleum-based fuels. The team will develop the requisite kinetic rules for specific reaction types and incorporate these into detailed kinetic mechanisms to predict the combustion performance of neat alternative fuels as well as blends of these fuels with conventional fuels. Reduced kinetic models will be then developed to allow solution of the coupled kinetics/transport problems. This is a collaboration between the Colorado School of Mines (CSM) and the Lawrence Livermore National Laboratory (LLNL). The CSM/LLNL team plans to build on the substantial progress made in recent years in developing accurate detailed chemical mechanisms for the oxidation and pyrolysis of conventional fuels. Particular emphasis will be placed upon reactions of the isoalkanes and the daughter radicals, especially tertiary radicals, formed by abstraction from the isoalkanes. The various components of the program are described. We have been developing the kinetic models for two iso-dodecane molecules, using the same kinetic modeling formalisms that were developed for the gasoline and diesel primary reference fuels. These mechanisms, and the thermochemical and transport coefficient submodels for them, are very close to completion at the time of this report, and we expect them to be available for kinetic simulations early in the coming year. They will provide a basis for prediction and selection of desirable F-T molecules for use in jet engine simulations, where we should be able to predict the ignition, combustion and emissions characteristics of proposed fuel components. These mechanisms include the reactions and chemical species needed to describe high temperature phenomena such as shock tube ignition and flammability behavior, and they will also include low temperature kinetics to describe other ignition phenomena such as compression ignition and knocking. During the past years, our hydrocarbon kinetics modeling group at LLNL has focused a great deal on fuels typical of gasoline and diesel fuel. About 10 years ago, we developed kinetic models for the fuel octane primary reference fuels, n-heptane [1] and iso-octane [2], which have 7 and 8 carbon atoms and are therefore representative of typical gasoline fuels. N-heptane represents the low limit of knock resistance with an octane number of 0, while iso-octane is very knock resistant with an octane number of 100. High knock resistance in iso-octane was attributed largely to the large fraction of primary C-H bonds in the molecule, including 15 of the 18 C-H bonds, and the high bond energy of these primary bonds plays a large role in this knock resistance. In contrast, in the much more ignitable n-heptane, 10 of its 16 C-H bonds are much less strongly bound secondary C-H bonds, leading to its very low octane number. All of these factors, as well as a similarly complex kinetic description of the equally important role of the transition state rings that transfer H atoms within the reacting fuel molecules, were quantified and collected into large kinetic reaction mechanisms that are used by many researchers in the fuel chemistry world.

Pitz, W J; Westbrook, C K

2009-07-30

247

Fuel burner and combustor assembly for a gas turbine engine  

DOEpatents

A fuel burner and combustor assembly for a gas turbine engine has a housing within the casing of the gas turbine engine which housing defines a combustion chamber and at least one fuel burner secured to one end of the housing and extending into the combustion chamber. The other end of the fuel burner is arranged to slidably engage a fuel inlet connector extending radially inwardly from the engine casing so that fuel is supplied, from a source thereof, to the fuel burner. The fuel inlet connector and fuel burner coact to anchor the housing against axial movement relative to the engine casing while allowing relative radial movement between the engine casing and the fuel burner and, at the same time, providing fuel flow to the fuel burner. For dual fuel capability, a fuel injector is provided in said fuel burner with a flexible fuel supply pipe so that the fuel injector and fuel burner form a unitary structure which moves with the fuel burner.

Leto, Anthony (Franklin Lakes, NJ)

1983-01-01

248

Diazido alkanes and diazido alkanols as combustion modifiers for liquid hydrocarbon ramjet fuels  

SciTech Connect

This invention relates to liquid-hydrocarbon jet fuels and more particularly to azido additives to liquid-hydrocarbon ramjet fuels. In most liquid-fueled combustors such as the ramjet, the fuel is directly introduced into the upstream flow section of the combustion chamber in the form of sprays of droplets. These droplets subsequently mix with the external gas, heat up, gasify, combust, and thereby release heat to provide the propulsion energy. It is therefore obvious that the rates of gasification and mixing would closely affect the chemical heat release rate and, consequently, such important performance parameters as combustion efficiency and the tendency to exhibit combustion instability. Accordingly, and object of this invention is to provide a new, improved jet fuel and provide new additives for jet fuels. A further object of this invention is to provide a more-efficient jet fuel and reduce the ignition time for jet fuels. Still, a further object of this invention is to improve the mixing characteristics of the jet-fuel spray.

Miller, R.S.

1986-07-03

249

Automotive gas turbine fuel control  

NASA Technical Reports Server (NTRS)

A fuel control system is reported for automotive-type gas turbines and particulary advanced gas turbines utilizing variable geometry components to improve mileage and reduce pollution emission. The fuel control system compensates for fuel density variations, inlet temperature variations, turbine vane actuation, acceleration, and turbine braking. These parameters are utilized to control various orifices, spool valves and pistons.

Gold, H. (inventor)

1978-01-01

250

Gas-deposit-alloy corrosion interactions in simulated combustion environments  

NASA Astrophysics Data System (ADS)

High temperature corrosion in aggressive coal combustion environments involves simultaneous corrosion reactions between combustion gases, ash deposits, and alloys. This research investigated the behavior of a ferritic steel (SA387-Gr11) and three weld claddings (309L SS, Alloy 72, and Alloy 622) in five combustion environments beneath solid deposits at 500°C for up to 1000 hours. The synthetic gases consisted of N2-CO-CO-H2-H2O-H 2S-SO2 mixtures that simulated a range of fuel-rich or fuel-lean combustion environments with a constant sulfur content. The synthetic deposits contained FeS2, FeS, Fe3O4 and/or carbon. Reaction kinetics was studied in individual gas-metal, gas deposit, and deposit-alloy systems. A test method was developed to investigate simultaneous gas-deposit-metal corrosion reactions. The results showed reaction kinetics varied widely, depending on the gas-alloy system and followed linear, parabolic, and logarithmic rate laws. Under reducing conditions, the alloys exhibited a range of corrosion mechanisms including carburization-sulfidation, sulfidation, and sulfidation-oxidation. Most alloys were not resistant to the highly reducing gases but offered moderate resistance to mixed oxidation-sulfidation by demonstrating parabolic or logarithmic behavior. Under oxidizing conditions, all of the alloys were resistant. Under oxidizing-sulfating conditions, alloys with high Fe or Cr contents sulfated whereas an alloy containing Mo and W was resistant. In the gas-deposit-metal tests, FeS2-bearing deposits were extremely corrosive to low alloy steel under both reducing and oxidizing conditions but they had little influence on the weld claddings. Accelerated corrosion was attributed to rapid decomposition or oxidation of FeS2 particles that generated sulfur-rich gases above the alloy surface. In contrast, FeS-type deposits had no influence under reducing conditions but they were aggressive to low alloy steel under oxidizing conditions. The extent of damage correlated with the initial sulfur content in the deposit. Fe3O4 in the deposit was beneficial because it acted as a sulfur getter or oxygen source. Carbon had a mixed effect. The reaction behavior was modeled using computational thermochemistry based on Gibbs free energy minimization. A calculation method was introduced to predict equilibrium corrosion microstructures and trace reaction paths in complex gas-deposit-metal environments. Kinetic factors were identified where equilibrium reaction products were not experimentally observed.

Luer, Kevin Raymond

251

Multiphase CFD-based models for chemical looping combustion process: Fuel reactor modeling  

SciTech Connect

Chemical looping combustion (CLC) is a flameless two-step fuel combustion that produces a pure CO2 stream, ready for compression and sequestration. The process is composed of two interconnected fluidized bed reactors. The air reactor which is a conventional circulating fluidized bed and the fuel reactor which is a bubbling fluidized bed. The basic principle is to avoid the direct contact of air and fuel during the combustion by introducing a highly-reactive metal particle, referred to as oxygen carrier, to transport oxygen from the air to the fuel. In the process, the products from combustion are kept separated from the rest of the flue gases namely nitrogen and excess oxygen. This process eliminates the energy intensive step to separate the CO2 from nitrogen-rich flue gas that reduce the thermal efficiency. Fundamental knowledge of multiphase reactive fluid dynamic behavior of the gas–solid flow is essential for the optimization and operation of a chemical looping combustor. Our recent thorough literature review shows that multiphase CFD-based models have not been adapted to chemical looping combustion processes in the open literature. In this study, we have developed the reaction kinetics model of the fuel reactor and implemented the kinetic model into a multiphase hydrodynamic model, MFIX, developed earlier at the National Energy Technology Laboratory. Simulated fuel reactor flows revealed high weight fraction of unburned methane fuel in the flue gas along with CO2 and H2O. This behavior implies high fuel loss at the exit of the reactor and indicates the necessity to increase the residence time, say by decreasing the fuel flow rate, or to recirculate the unburned methane after condensing and removing CO2.

Jung, Jonghwun (ANL); Gamwo, I.K.

2008-04-21

252

Effect of flow field for colorless distributed combustion (CDC) for gas turbine combustion  

Microsoft Academic Search

Colorless distributed combustion (CDC) investigated here is focused on gas turbine combustion applications due to its significant benefits for, much reduced NOx emissions and noise reduction, and significantly improved pattern factor. CDC is characterized by distributed reaction zone of combustion which leads to uniform thermal field and avoidance of hot spot regions to provide significant improvement in pattern factor, lower

Vaibhav K. Arghode; Ashwani K. Gupta

2010-01-01

253

Broad specification fuels combustion technology program  

NASA Technical Reports Server (NTRS)

Design and development efforts to evolve promising aircraft gas turbine combustor configurations for burning broadened-properties fuels were discussed. Design and experimental evaluations of three different combustor concepts in sector combustor rig tests was conducted. The combustor concepts were a state of the art single-annular combustor, a staged double-annular combustor, and a short single-annular combustor with variable geometry to control primary zone stoichiometry. A total of 25 different configurations of the three combustor concepts were evaluated. Testing was conducted over the full range of CF6-80A engine combustor inlet conditions, using four fuels containing between 12% and 14% hydrogen by weight. Good progress was made toward meeting specific program emissions and performance goals with each of the three combustor concepts. The effects of reduced fuel hydrogen content, including increased flame radiation, liner metal temperature, smoke, and NOx emissions were documented. The most significant effect on the baseline combustor was a projected 33% life reduction, for a reduction from 14% to 13% fuel hydrogen content, due to increased liner temperatures.

Dodds, W. J.; Ekstedt, E. E.

1984-01-01

254

Biomass Fuel Characterization : Testing and Evaluating the Combustion Characteristics of Selected Biomass Fuels : Final Report May 1, 1988-July, 1989.  

SciTech Connect

Results show that two very important measures of combustion efficiency (gas temperature and carbon dioxide based efficiency) varied by only 5.2 and 5.4 percent respectively. This indicates that all nine different wood fuel pellet types behave very similarly under the prescribed range of operating parameters. The overall mean efficiency for all tests was 82.1 percent and the overall mean temperature was 1420 1{degree}F. Particulate (fly ash) ad combustible (in fly ash) data should the greatest variability. There was evidence of a relationship between maximum values for both particulate and combustible and the percentages of ash and chlorine in the pellet fuel. The greater the percentage of ash and chlorine (salt), the greater was the fly ash problem, also, combustion efficiency was decreased by combustible losses (unburned hydrocarbons) in the fly ash. Carbon monoxide and Oxides of Nitrogen showed the next greatest variability, but neither had data values greater than 215.0 parts per million (215.0 ppm is a very small quantity, i.e. 1 ppm = .001 grams/liter = 6.2E-5 1bm/ft{sup 3}). Visual evidence indicates that pellets fuels produced from salt laden material are corrosive, produce the largest quantities of ash, and form the only slag or clinker formations of all nine fuels. The corrosion is directly attributable to salt content (or more specifically, chloride ions and compounds formed during combustion). 45 refs., 23 figs., 19 tabs.

Bushnell, Dwight J.; Haluzok, Charles; Dadkhah-Nikoo, Abbas

1990-04-01

255

LOW NOX STRATEGY FOR COMBUSTING HIGH NITROGEN CONTENT FUELS  

EPA Science Inventory

The report gives results of an evaluation of a multistaged combustion urner (designed for in-furnace NOx control and high combustion efficieiicy) for [high nitrogen content fuel and waste incineration application in a 1.0 MW package boiler. simulator. A low NOx precombustion cham...

256

Reaction Kinetics of Fuel Formation for In-Situ Combustion  

Microsoft Academic Search

Chemical reactions believed to cause fuel formation for in-situ combustion have been studied and modeled. A thin, packed bed of sand\\/oil mixture is heated under nitrogen flow at linearly increasing temperatures, simulating the approach of a combustion front. Analysis of gases produced from the reaction cell revealed that pyrolysis of crude oil in porous media goes through three overlapping stages:

Sidqi Abu-Khamsin; William Brigham; Henry Ramey Jr.

1988-01-01

257

Combustion of hydrocarbon fuels within porous inert media  

Microsoft Academic Search

There has been a recent surge of interest in the combustion of hydrocarbon fuels within porous inert media. The interest has been directed by the needs of industry to develop high performance radiant heaters while complying with increasingly stringent emissions regulations. This paper reviews the processes associated with non-catalytic combustion within porous media, and describes related experimental and modeling research.

J. R. Howell; M. J. Hall; J. L. Ellzey

1996-01-01

258

Combustion gas temperature in a prechamber spark ignition engine measured by infrared pyrometer  

SciTech Connect

To obtain a more reasonable model of torch combustion in a spark ignition engine with a vertical or horizontal prechamber, the instantaneous temperatures of combustion gas are measured by an infrared absorption-emission pyrometer with a narrow band pass filter for CO/sub 2/ gas, while changing the torch nozzle area and air-fuel ratio. The gas temperature diagrams indicate that the ignition timing, flame propagation and combustion duration in the main chamber with vertical prechamber differ entirely from those with horizontal one. The fact is verified by comparing them with the heat release rates obtained from the pressure diagrams and with the flame propagation taken by means of high-speed photography. The measured gas temperature diagrams are, therefore, found to provide a lot of useful and local information concerning the combustion process and the engine performance in the prechamber engines.

Sakurauchi, Y.; Ryu, H.; Iijima, T.; Asanuma, T.

1987-01-01

259

Dynamic instabilities in spark-ignited combustion engines with high exhaust gas recirculation  

NASA Astrophysics Data System (ADS)

We propose a cycle-resolved dynamic model for combustion instabilities in spark-ignition engines operating with high levels of exhaust gas recirculation (EGR). We account for the complex combustion response to cycle-to-cycle feedback by utilizing a global probability distribution that describes the pre-spark state of in-cylinder fuel mixing. The proposed model does a good job of simulating combustion instabilities observed in both lean-fueling engine experiments and in experiments where nitrogen dilution is used to simulate some of the combustion inhibition of EGR. When used to simulate high internal EGR operation, the model exhibits a range of global bifurcations and chaos that appear to be very robust. We use the model to show that it should be possible to reduce high EGR combustion instabilities by switching from internal to external EGR.

Daw, C. Stuart; Finney, Charles E. A.

2011-04-01

260

Method of controlling the combustion of liquid fuel  

SciTech Connect

The present invention relates to a method of controlling a substantially stoichiometric combustion of liquid fuels in a burner assembly wherein a stream of compact or atomized fuel is produced by means of an orifice or nozzle (e.g. injection, pressure, rotary atomizing nozzle) and fed into a mixing and atomizing zone in accordance with the preferably adjustable, nozzle input pressure, wherein at least part of the combustion air as an atomizing medium is introduced from the side of the axis of the fuel stream, with the flow of such air being adapted to be controlled with respect to throughput (flow rate) and flow velocity, and including a subsequent combustion of the fuel/air mixture within a combustion zone downstream of said mixing zone.

Graat, J.W.; Remie, H.J.

1982-06-15

261

Experimental Investigation of Fuel-Reactivity Controlled Compression Ignition (RCCI) Combustion Mode in a Multi-Cylinder, Light-Duty Diesel Engine  

SciTech Connect

An experimental study was performed to provide the combustion and emission characteristics resulting from fuel-reactivity controlled compression ignition (RCCI) combustion mode utilizing dual-fuel approach in a light-duty, multi-cylinder diesel engine. In-cylinder fuel blending using port fuel injection of gasoline before intake valve opening (IVO) and early-cycle, direct injection of diesel fuel was used as the charge preparation and fuel blending strategy. In order to achieve the desired auto-ignition quality through the stratification of the fuel-air equivalence ratio ( ), blends of commercially available gasoline and diesel fuel were used. Engine experiments were performed at an engine speed of 2300rpm and an engine load of 4.3bar brake mean effective pressure (BMEP). It was found that significant reduction in both nitrogen oxide (NOx) and particulate matter (PM) was realized successfully through the RCCI combustion mode even without applying exhaust gas recirculation (EGR). However, high carbon monoxide (CO) and hydrocarbon (HC) emissions were observed. The low combustion gas temperature during the expansion and exhaust processes seemed to be the dominant source of high CO emissions in the RCCI combustion mode. The high HC emissions during the RCCI combustion mode could be due to the increased combustion quenching layer thickness as well as the -stratification at the periphery of the combustion chamber. The slightly higher brake thermal efficiency (BTE) of the RCCI combustion mode was observed than the other combustion modes, such as the conventional diesel combustion (CDC) mode, and single-fuel, premixed charge compression ignition (PCCI) combustion mode. The parametric study of the RCCI combustion mode revealed that the combustion phasing and/or the peak cylinder pressure rise rate of the RCCI combustion mode could be controlled by several physical parameters premixed ratio (rp), intake swirl intensity, and start of injection (SOI) timing of directly injected fuel unlike other low temperature combustion (LTC) strategies.

Cho, Kukwon [ORNL; Curran, Scott [ORNL; Prikhodko, Vitaly Y [ORNL; Sluder, Scott [ORNL; Parks, II, James E [ORNL; Wagner, Robert M [ORNL

2011-01-01

262

Characterization of oscillations during premix gas turbine combustion  

Microsoft Academic Search

The use of premix combustion in stationary gas turbines can produce very low levels of NOâ emissions. This benefit is widely recognized, but turbine developers routinely encounter problems with combustion oscillations during the testing of new premix combustors. Because of the associated pressure fluctuations, combustion oscillations must be eliminated in a final combustor design. Eliminating these oscillations is often time-consuming

G. A. Richards; M. C. Janus

1998-01-01

263

Performance of a flameless combustion furnace using biogas and natural gas.  

PubMed

Flameless combustion technology has proved to be flexible regarding the utilization of conventional fuels. This flexibility is associated with the main characteristic of the combustion regime, which is the mixing of the reactants above the autoignition temperature of the fuel. Flameless combustion advantages when using conventional fuels are a proven fact. However, it is necessary to assess thermal equipments performance when utilizing bio-fuels, which usually are obtained from biomass gasification and the excreta of animals in bio-digesters. The effect of using biogas on the performance of an experimental furnace equipped with a self-regenerative Flameless burner is reported in this paper. All the results were compared to the performance of the system fueled with natural gas. Results showed that temperature field and uniformity are similar for both fuels; although biogas temperatures were slightly lower due to the larger amount of inert gases (CO(2)) in its composition that cool down the reactions. Species patterns and pollutant emissions showed similar trends and values for both fuels, and the energy balance for biogas showed a minor reduction of the efficiency of the furnace; this confirms that Flameless combustion is highly flexible to burn conventional and diluted fuels. Important modifications on the burner were not necessary to run the system using biogas. Additionally, in order to highlight the advantages of the Flameless combustion regime, some comparisons of the burner performance working in Flameless mode and working in conventional mode are presented. PMID:19944602

Colorado, A F; Herrera, B A; Amell, A A

2010-04-01

264

The N.A.C.A. Combustion Chamber Gas-sampling Valve and Some Preliminary Test Results  

NASA Technical Reports Server (NTRS)

A gas sampling valve of the inertia-operated type was designed for procuring samples of the gases in the combustion chamber of internal combustion engines at identical points in successive cycles so that the analysis of the gas samples thus procured may aid in the study of the process of combustion. The operation of the valve is described. The valve was used to investigate the CO2 content of gases taken from the quiescent combustion chamber of a high speed compression-ignition engine when operating with two different multiple-orifice fuel injection nozzles. An analysis of the gas samples thus obtained shows that the state of quiescence in the combustion chamber is maintained during the combustion of the fuel.

Spanogle, J A; Buckley, E C

1933-01-01

265

Fuel Vapor Pressures and the Relation of Vapor Pressure to the Preparation of Fuel for Combustion in Fuel Injection Engines  

NASA Technical Reports Server (NTRS)

This investigation on the vapor pressure of fuels was conducted in connection with the general research on combustion in fuel injection engines. The purpose of the investigation was to study the effects of high temperatures such as exist during the first stages of injection on the vapor pressures of several fuels and certain fuel mixtures, and the relation of these vapor pressures to the preparation of the fuel for combustion in high-speed fuel injection engines.

Joachim, William F; Rothrock, A M

1930-01-01

266

Hydrocarbon-fuel/combustion-chamber-liner materials compatibility  

NASA Technical Reports Server (NTRS)

Results of material compatibility experiments using hydrocarbon fuels in contact with copper-based combustion chamber liner materials are presented. Mil-Spec RP-1, n- dodecane, propane, and methane fuels were tested in contact with OFHC, NASA-Z, and ZrCu coppers. Two distinct test methods were employed. Static tests, in which copper coupons were exposed to fuel for long durations at constant temperature and pressure, provided compatibility data in a precisely controlled environment. Dynamic tests, using the Aerojet Carbothermal Test Facility, provided fuel and copper compatibility data under realistic booster engine service conditions. Tests were conducted using very pure grades of each fuel and fuels to which a contaminant, e.g., ethylene or methyl mercaptan, was added to define the role played by fuel impurities. Conclusions are reached as to degradation mechanisms and effects, methods for the elimination of these mechanisms, selection of copper alloy combustion chamber liners, and hydrocarbon fuel purchase specifications.

Gage, Mark L.

1990-01-01

267

Internal combustion engine method for delayed reaction stratified combustion  

Microsoft Academic Search

A method of delayed reaction stratified combustion for internal combustion engines comprising burning a compressed fast burning rich air-fuel mixture during an initial portion of a combustion event, adding supplemental diluting air optimally with recirculated exhaust gas (EGR) during an intermediate portion of such combustion event and completing combustion during latter portions of the combustion event. Suggested timing and mixture

Cataldo

1984-01-01

268

Combustion characteristics of GAP-coated boron particles and the fuel-rich solid propellant  

SciTech Connect

A process was employed that permits the coating of energetic glycidyl azide polymer (GAP) on the boron surface. Ignition and combustion behavior of single particle pure crystalline boron and GAP-coated boron at atmospheric pressure was studied experimentally by injecting the particles into the stream of hot gaseous environment of a flat-flame burner using premixed propane-oxygen-nitrogen gases. Chopped streak photographic observation was used to measure the ignition and combustion time. The flame temperature was fixed around 2,343 K, but under wider O{sub 2} level range than previous investigations. Measurement results show that GAP coating can shorten boron particle ignition delay time, however, the effect diminishes as the O{sub 2} level in combustion gas decreases. Possible mechanisms based on relevant reactions and heat effects were proposed. Combustion characteristics of fuel-rich solid propellants based on GAP-coated amorphous boron particles and uncoated ones were compared using different techniques such as combustion phenomena observations by a windowed strand burner, quenched propellant surface morphology analysis by scanning electron microscope, and combustion residues size analysis from the quenched particle collection bomb experiments. It was concluded that GAP-coated amorphous-boron-based fuel-rich propellants exhibit more vigorous combustion phenomena, higher burning rates, and a lesser extent of residue agglomeration than the uncoated baseline propellant. Moreover, reaction mechanisms were proposed to elucidate the combustion products obtained in this study.

Shyu, I.M. [Chung Cheng Inst. of Technology, Tashi (Taiwan, Province of China). Dept. of Applied Chemistry] [Chung Cheng Inst. of Technology, Tashi (Taiwan, Province of China). Dept. of Applied Chemistry; Liu, T.K. [Chung Shan Inst. of Science and Technology, Lungtan (Taiwan, Province of China). Chemical System Research Division] [Chung Shan Inst. of Science and Technology, Lungtan (Taiwan, Province of China). Chemical System Research Division

1995-03-01

269

Combustion characterization of beneficiated coal-based fuels  

SciTech Connect

The objectives of this project include: (1) the development of an engineering data base which will provide detailed information on the properties of BCFs influencing combustion, ash deposition, ash erosion, particulate collection, and missions; and (2) the application of this technical data base to predict the performance and economic impacts of firing the BCFs in various commercial boiler designs. The technical approach used to develop the technical data includes: bench-scale fuel property, combustion, and ash deposition tests; pilot-scale combustion and ash effects test; and full-scale combustion tests.

Chow, O.K.; Nsakala, N.Y.

1990-06-01

270

Combustion of waste fuels in a fluidized-bed boiler  

Microsoft Academic Search

This paper reports on a project whose objectives are to determine the impact of the waste fuels on Atmospheric Fluidized Bed Combustion (AFBC) operating procedures, boiler performance, and emissions and to assess the potential for fuel-specific operating problems. The low-grade waste fuels investigated are hogged railroad ties, shredded rubber tires, peat, refuse-derived fuel, and one or more agricultiral wastes. The

J. Zylkowski; S. Ehrlich

1983-01-01

271

Dynamic instabilities in spark-ignited combustion engines with high exhaust gas recirculation  

SciTech Connect

We propose a cycle-resolved dynamic model for combustion instabilities in spark-ignition engines operating with high levels of exhaust gas recirculation (EGR). High EGR is important for increasing fuel efficiency and implementing advanced low-emission combustion modes such as homogenous charge compression ignition (HCCI). We account for the complex combustion response to cycle-to-cycle feedback by utilizing a global probability distribution that describes the pre-spark state of in-cylinder fuel mixing. The proposed model does a good job of simulating combustion instabilities observed in both lean-fueling engine experiments and in experiments where nitrogen dilution is used to simulate some of the combustion inhibition of EGR. When used to simulate high internal EGR operation, the model exhibits a range of global bifurcations and chaos that appear to be very robust. We use the model to show that it should be possible to reduce high EGR combustion instabilities by switching from internal to external EGR. We also explain why it might be helpful to deliberately stratify the fuel in the pre-spark gas mixture. It might be possible to extend the simple approach used in this model to other chemical reaction systems with spatial inhomogeneity.

Daw, C Stuart [ORNL; FINNEY, Charles E A [ORNL

2011-01-01

272

Sulphur impacts during pulverised coal combustion in oxy-fuel technology for carbon capture and storage  

Microsoft Academic Search

The oxy-fuel process is one of three carbon capture technologies which supply CO2 ready for sequestration – the others being post-combustion capture and IGCC with carbon capture. As yet no technology has emerged as a clear winner in the race to commercial deployment. The oxy-fuel process relies on recycled flue gas as the main heat carrier through the boiler and

Rohan Stanger; Terry Wall

2011-01-01

273

Developments in integrated pollutant removal for low-emission oxy-fuel combustion  

SciTech Connect

A complete coal combustion and flue gas treatment scheme was designed, constructed, and operated at bench scale as a product of cooperative research between US DOE’s Albany Research Center (ARC) and Jupiter Oxygen Corporation. The combustion gas generated using this oxy-fuel coal combustion process was effectively captured using an integrated pollutant removal (IPR) process. Supporting laboratory-scale research focuses on elements of IPR such as extraction of particulates, SO2, and mercury, and on the character of the liquid and vapor phase compositions for the CO2 - N2 - O2 mixture at the temperature and pressure conditions found at the end of the process. Future pilot-scale work will be necessary to generate economic and engineering data that will apply to full-scale oxy-fuel/IPR systems.

Gerdemann, Stephen J.; Summers, Cathy A.; Oryshchyn, Danylo B.; Patrick, Brian (Jupiter Oxygen Corp.); Ochs, Thomas L.

2005-09-01

274

Combustion of hydrogen in a two-dimensional duct with step fuel injectors  

NASA Technical Reports Server (NTRS)

An investigation of the combustion of hydrogen perpendicularly injected from step fuel injectors into a Mach 2.72, 2100 K vitiated test gas was conducted. The model simulated the flow between the center and side struts of an integrated scramjet module at Mach 7 flight and an altitude of 29 km. Parametric variation included equivalence ratio, fuel dynamic pressure ratio, and area distribution of the model. The overall area ratio of the model was held constant at 2.87. The data analysis indicated that no measurable improvement in mixing or combustion efficiency was obtained by varying the fuel dynamic pressure ratio from 0.79 to 2.45. Computations indicated approximately 80 percent of the fuel was mixed so that it could react; however, only approximately 50 percent of the mixed fuel actually reacted in two test configurations, and 74 percent in later tests where less area expansion of the flow occurred.

Eggers, J. M.; Reagon, P. G.; Gooderum, P. B.

1978-01-01

275

CO2 and H2O diluted oxy-fuel combustion for zero-emission power  

SciTech Connect

Concerns about climate change have encouraged significant interest in concepts for zero-emission power generation systems. These systems are intended to produce power without releasing CO2 into the atmosphere. One method to achieve this goal is to produce hydrogen from the gasification of fossil or biomass fuels. Using various membrane and reforming technologies, the carbon in the parent fuel can be shifted to CO2 and removed from the fuel stream, followed by direct CO2 sequestration. The hydrogen fuel can be used directly in gas turbines fitted with low-NOx combustors. A second approach to producing zero-emission power is to replace the nitrogen diluent that accompanies conventional combustion in air with either CO2 or H2O. In this concept, CO2 or H2O is added to oxygen to control combustion temperatures in oxygen–fuel reactions. In the absence of nitrogen, the primary combustion products for any hydrocarbon under lean conditions are then simply CO2 and H2O. Thus, merely cooling the exhaust stream condenses the water and produces an exhaust of pure CO2, ready for sequestration. The dilute oxy-fuel combustion strategy can be incorporated in power cycles that are similar to Brayton or Rankine configurations, using CO2 or H2O as the primary diluent respectively. While the relativemerits of the various strategies to zero-emission power are the subject of various technical and economic studies, very little work has focused on defining the combustion issues associated with the dilute oxy-fuel option. In this paper, the expected combustion performance of CO2 and H2O diluted systems are compared. Experimental results from a high-pressure oxy-fuel combustor are also presented.

G A Richards; K H Casleton; B T Chorpening

2005-01-01

276

Development of catalytic combustion technology for single-digit emissions from industrial gas turbines  

Microsoft Academic Search

Catalytic combustion has demonstrated potential for attaining the firing temperatures of current and next generation gas turbines with nitrogen oxides (NOx) production less than 3 parts-per-million by volume (ppmv), using natural gas fuel. The technology necessary to achieve this extremely low emissions performance with typical heavy-duty industrial and utility gas turbine operating cycle conditions, has been under development as a

Kenneth W Beebe; Kristina D Cairns; Vinod K Pareek; Sarento G Nickolas; James C Schlatter; Toshiaki Tsuchiya

2000-01-01

277

Combustible gas production from sewage sludge with a downdraft gasifier  

Microsoft Academic Search

Recently, sewage sludge has particularly become an important problem all over the world because of its harmful impacts on the environment and living beings. It should be converted to combustible gas or useful energy in order to remove all its negative effects and to contribute to a significant portion of the power generation. In this study, combustible gas production from

Adnan Midilli; Murat Dogru; Colin R. Howarth; Mike J. Ling; Teoman Ayhan

2001-01-01

278

Coal-water slurry combustion in gas turbines  

Microsoft Academic Search

This paper presents preliminary results of a program to investigate the key technologies for burning coal-water slurries in gas turbines. Results are given for slurry atomization and combustion testing and analyses performed at conditions typical for gas turbine applications. Significant progress has been made toward the understanding of slurry combustion and ash deposition phenomena. Confidence has been gained to the

F. W. Staub; S. G. Kimura; C. L. Spiro; M. W. Horner

1988-01-01

279

Coal-water slurry combustion in gas turbines  

Microsoft Academic Search

This paper presents preliminary results of a program to investigate the key technologies for burning coal-water slurries in gas turbines. Results are given for slurry atomization and combustion testing and analyses performed at conditions typical for gas turbine applications. Significant progress has been made toward the understanding of slurry combustion and ash deposition phenomena. Confidence has been gained to the

F. W. Staub; S. G. Kimura; C. L. Spiro; M. W. Horner

1989-01-01

280

Combustion characteristics of dry coal-powder-fueled adiabatic diesel engine: Final report  

SciTech Connect

This report describes the progress and findings of a research program aimed at investigating the combustion characteristics of dry coal powder fueled diesel engine. During this program, significant achievements were made in overcoming many problems facing the coal-powder-fueled engine. The Thermal Ignition Combustion System (TICS) concept was used to enhance the combustion of coal powder fuel. The major coal-fueled engine test results and accomplishments are as follows: design, fabrication and engine testing of improved coal feed system for fumigation of coal powder to the intake air; design, fabrication and engine testing of the TICS chamber made from a superalloy material (Hastelloy X); design, fabrication and engine testing of wear resistant chrome oxide ceramic coated piston rings and cylinder liner; lubrication system was improved to separate coal particles from the contaminated lubricating oil; control of the ignition timing of fumigated coal powder by utilizing exhaust gas recirculation (EGR) and variable TICS chamber temperature; coal-fueled engine testing was conducted in two configurations: dual fuel (with diesel pilot) and 100% coal-fueled engine without diesel pilot or heated intake air; cold starting of the 100% coal-powder-fueled engine with a glow plug; and coal-fueled-engine was operated from 800 to 1800 rpm speed and idle to full load engine conditions.

Kakwani, R.M.; Kamo, R.

1989-01-01

281

Semi-volatile and particulate emissions from the combustion of alternative diesel fuels.  

PubMed

Motor vehicle emissions are a major anthropogenic source of air pollution and contribute to the deterioration of urban air quality. In this paper, we report results of a laboratory investigation of particle formation from four different alternative diesel fuels, namely, compressed natural gas (CNG), dimethyl ether (DME), biodiesel, and diesel, under fuel-rich conditions in the temperature range of 800-1200 degrees C at pressures of approximately 24 atm. A single pulse shock tube was used to simulate compression ignition (CI) combustion conditions. Gaseous fuels (CNG and DME) were exposed premixed in air while liquid fuels (diesel and biodiesel) were injected using a high-pressure liquid injector. The results of surface analysis using a scanning electron microscope showed that the particles formed from combustion of all four of the above-mentioned fuels had a mean diameter less than 0.1 microm. From results of gravimetric analysis and fuel injection size it was found that under the test conditions described above the relative particulate yields from CNG, DME, biodiesel, and diesel were 0.30%. 0.026%, 0.52%, and 0.51%, respectively. Chemical analysis of particles showed that DME combustion particles had the highest soluble organic fraction (SOF) at 71%, followed by biodiesel (66%), CNG (38%) and diesel (20%). This illustrates that in case of both gaseous and liquid fuels, oxygenated fuels have a higher SOF than non-oxygenated fuels. PMID:11219694

Sidhu, S; Graham, J; Striebich, R

2001-01-01

282

Effects of super heating of heavy fuels on combustion and performance in DI diesel engines  

SciTech Connect

This paper is concerned with the effects of temperature of heavy fuels on combustion and engine performance in a naturally aspirated DI diesel engine. Engine performance and exhaust gas emissions were measured for rapeseed oil, B-heavy oil, and diesel fuel at fuel temperatures from 40/sup 0/C to 400/sup 0/C. With increased fuel temperature, mainly from improved efficiency of combustion there were significant reductions in the specific energy consumption and smoke emissions. It was found that the improvements were mainly a function of the fuel viscosity, and it was independent of the kind of fuel. The optimum temperature of the fuels with regard to specific energy consumption and smoke emission is about 90/sup 0/C for diesel fuel, 240/sup 0/C for B-heavy oil, and 300/sup 0/C for rapeseed oil. At these temperatures, the viscosities of the fuels show nearly identical value, 0.9 - 3 cSt. The optimum viscosity tends to increase slightly with increases in the swirl ratio in the combustion chamber.

Murayama, T.; Oh, Y.; Kido, A.; Chikahisa, T.; Itow, K.

1986-01-01

283

Stratified charge combustion system and method for gaseous fuel internal combustion engines  

SciTech Connect

This patent describes a stratified charge combustion system for use in a gaseous fuel internal combustion engine. This system consists of: (a) a combustion chamber; (b) an ignition; (c) a gaseous fuel injection valve assembly in communication with the combustion chamber and in spaced relationship from the ignition source with a portion of the inside surfaces extending between the fuel injection valve assembly and the ignition source. The fuel valve assembly defines an entry port for the entrance of gaseous fuel, the entry port is recessed outside of a fixed inside surface. (d) means for pressuring the gaseous fuel prior to injection; and (e) a curved transitional surface extending from the entry port toward the portion of the inside surfaces extending between the fuel injection valve assembly and the ignition source. The curved transitional surface curves away from the direction of the entry port. The curved transitional surface has a curvature for the particular direction and configuration of the entry port. The particular configuration of the portion of the inside surfaces extends between the injection valve assembly and the ignition source. The particular arrangment of the fuel injection valve assembly in the combustion chamber, and for the particular pressure of the gaseous fuel is to produce the Coanda Effect in the injected gaseous fuel flow after it passes through the entry port and follows the curved transitional surface under the Coanda Effect. As the curved transitional surface curves away from the direction of the entry port, a flow is produced of the gaseous fuel that clings to and follows the particular configuration of the inside surfaces to the ignition source.

Rhoades, W.A. Jr.

1986-03-11

284

Comparison of numerical simulation results for transport and thermodynamic properties of the solid fuels combustion products with experimental data  

NASA Astrophysics Data System (ADS)

Comparison of calculation results of transport properties of the solid fuels combustion products was made with known experimental data. Calculation was made by means of the modified program TETRAN developed in G.M. Krzhizhanovsky Power Engineering Institute. The calculation was spent with chemical reactions and phase transformations occurring during combustion. Also ionization of products of solid fuels combustion products at high temperatures was taken into account. In the capacity of fuels various Russian coals and some other solid fuels were considered. As a result of density, viscosity and heat conductivity calculation of a gas phase of solid fuels combustion products the data has been obtained in a range of temperatures 500-20000 K. This comparison has shown good convergence of calculation results with experiment.

Shmelkov, Yuriy; Samujlov, Eugueny

2012-04-01

285

Performance gains by using heated natural-gas fuel in an annular turbojet combustor  

NASA Technical Reports Server (NTRS)

A full-scale annular turbojet combustor was tested with natural gas fuel heated from ambient temperature to 800 K (980 F). In all tests, heating the fuel improved combustion efficiency. Two sets of gaseous fuel nozzles were tested. Combustion instabilities occurred with one set of nozzles at two conditions: one where the efficiency approached 100 percent with the heated fuel; the other where the efficiency was very poor with the unheated fuel. The second set of nozzles exhibited no combustion instability. Altitude relight tests with the second set showed that relight was improved and was achievable at essentially the same condition as blowout when the fuel temperature was 800 K (980 F).

Marchionna, N. R.

1973-01-01

286

Experimental Study of Unsupported Nonane fuel Droplet Combustion in Microgravity  

NASA Technical Reports Server (NTRS)

Soot formation in droplet flames is the basic component of the particulate emission process that occurs in spray combustion. The complexity of soot formation motivates a one-dimensional transport condition which has obvious advantages in modeling. Recent models of spherically symmetric droplet combustion have made this assumption when incorporating such aspects as detailed chemistry and radiation. Interestingly, spherical symmetry does not necessarily restrict the results because it has been observed that the properties of carbon formed in flames are not strongly affected by the nature of the fuel or flaming configuration. What is affected, however, are the forces acting on the soot aggregates and where they are trapped by a balance of drag and thermophoretic forces. The distribution of these forces depends on the transport conditions of the flame. Prior studies of spherical droplet flames have examined the droplet burning history of alkanes, alcohols and aromatics. Data are typically the evolution of droplet, flame, extinction, and soot shell diameters. These data are only now just beginning to find their way into comprehensive numerical models of droplet combustion to test proposed oxidation schemes for fuels such as methanol and heptane. In the present study, we report new measurements on the burning history of unsupported nonane droplets in a convection-free environment to promote spherical symmetry. The far-field gas is atmospheric pressure air at room temperature. The evolution of droplet diameter was measured using high speed cine photography of a spark-ignited, droplet within a confined volume in a drop tower. The initial droplet diameters varied between 0.5 mm and 0.6 mm. The challenge of unsupported droplets is to form, deploy and ignite them with minimal disturbance, and then to keep them in the camera field of view. Because of the difficulty of this undertaking, more sophisticated diagnostics for studying soot than photographic were not used. Supporting the test droplet by a fiber fixes the droplet position but the fiber can perturb the burning process especially for a sooting fuel. Prior studies on heptane showed little evidence for soot formation due to g-droplets of similar size the relationship between sooting and droplet diameter. For nonane droplets we expect increased sooting due to the greater number of carbon atoms. As a sooting droplet burns and its diameter decreases, proportionally less soot should form. This reduced soot, as well as the influence of soot formed earlier in the burning process which collects in a 'shell', on heat transport to the flame offers the potential for a time-varying burning rate. Such an effect was investigated and revealed in results reported here. Speculation is offered for the cause of this effect and its possible relation to soot formation.

Callahan, B. J.; Avedisian, C. T.; Hertzog, D. E.; Berkery, J. W.

1999-01-01

287

Calculation of combustion gas flow rate and residence time based on stack gas data  

Microsoft Academic Search

In many situations, it is desired to estimate the combustion chamber gas residence time of operating combustion systems. This is typically accomplished by performing a mass and energy balance around the combustion chamber. Unfortunately, the detailed physical, chemical, and thermodynamic data needed for each of the feed streams, effluents, and combustion gases are often not readily available. Further, a rigorous

Anthony R. Eicher

2000-01-01

288

Supersonic combustion engine and method of combustion initiation and distribution  

SciTech Connect

A supersonic combustion ramjet engine having a combustor with a combustion zone intended to channel gas flow at relatively high speed therethrough, the engine comprising: means for substantially continuously supplying fuel into the combustion zone; and means for substantially instantaneously igniting a volume of fuel in the combustion zone for providing a spatially controlled combustion distribution, the igniting means having means for providing a diffuse discharge of energy into the volume, the volume extending across a substantially complete cross-sectional area of the combustion zone, the means for discharging energy being capable of generating free radicals within the volume of reactive fuel in the combustion zone such that fuel in the volume can initiate a controlled relatively rapid combustion of fuel in the combustion zone whereby combustion distribution in relatively high speed gas flows through the combustion zone can be initiated and controlled without dependence upon a flame holder or relatively high local static temperature in the combustion zone.

Stickler, D.B.; Ballantyne, A.; Kyuman Jeong.

1993-06-29

289

Sulfur emission from Victorian brown coal under pyrolysis, oxy-fuel combustion and gasification conditions.  

PubMed

Sulfur emission from a Victorian brown coal was quantitatively determined through controlled experiments in a continuously fed drop-tube furnace under three different atmospheres: pyrolysis, oxy-fuel combustion, and carbon dioxide gasification conditions. The species measured were H(2)S, SO(2), COS, CS(2), and more importantly SO(3). The temperature (873-1273 K) and gas environment effects on the sulfur species emission were investigated. The effect of residence time on the emission of those species was also assessed under oxy-fuel condition. The emission of the sulfur species depended on the reaction environment. H(2)S, SO(2), and CS(2) are the major species during pyrolysis, oxy-fuel, and gasification. Up to 10% of coal sulfur was found to be converted to SO(3) under oxy-fuel combustion, whereas SO(3) was undetectable during pyrolysis and gasification. The trend of the experimental results was qualitatively matched by thermodynamic predictions. The residence time had little effect on the release of those species. The release of sulfur oxides, in particular both SO(2) and SO(3), is considerably high during oxy-fuel combustion even though the sulfur content in Morwell coal is only 0.80%. Therefore, for Morwell coal utilization during oxy-fuel combustion, additional sulfur removal, or polishing systems will be required in order to avoid corrosion in the boiler and in the CO(2) separation units of the CO(2) capture systems. PMID:23301852

Chen, Luguang; Bhattacharya, Sankar

2013-02-01

290

Air-fuel ratio control apparatus of a fuel supply system for an internal combustion engine  

Microsoft Academic Search

An air-fuel ratio control apparatus for an internal combustion engine has an air valve disposed in an intake passage downstream of a throttle valve to cooperate therewith to define an air pressure chamber and operative to maintain a substantially constant pressure therein. A fuel circuit includes a fuel discharge port open to the intake passage and a fuel-metering orifice operatively

T. Ando; M. Minoura; K. Motosugi; S. Sekiya; M. Sumiyoshi; Y. Takeuchi; J. Uozumi

1980-01-01

291

Combustion characterization of beneficiated coal-based fuels  

SciTech Connect

The Pittsburgh Energy Technology Center of the US Department of Energy has contracted with Combustion Engineering, Inc. (CE) to perform a three-year project on Combustion Characterization of Beneficiated Coal-Based Fuels.'' The beneficiated coals are produced by other contractors under the DOE Coal Preparation Program. Several contractor-developed advanced coal cleaning processes are being run at the cleaning facility in Homer City, Pennsylvania, to produce 20-ton batches of fuels for shipment to CE's laboratory in Windsor, Connecticut. CE then processes the products into either a coal-water fuel (CVVT) or a dry microfine pulverized coal (DMPC) form for combustion testing. The objectives of this project include: (1) the development of an engineering data base which will provide detailed information on the properties of BCFs influencing combustion, ash deposition, ash erosion, particulate collection, and emissions; and (2) the application of this technical data base to predict the performance and economic impacts of firing the BCFs in various commercial boiler designs. The technical approach used to develop the technical data includes: bench-scale fuel property, combustion, and ash deposition tests; pilot-scale combustion and ash effects tests; and full-scale combustion tests. Subcontractors to CE to perform parts of the test work are the Massachusetts Institute of Technology (MIT), Physical Science, Inc. Technology Company (PSIT) and the University of North Dakota Energy and Environmental Research Center (UNDEERC). Twenty fuels will be characterized during the three-year base program: three feed coals, fifteen BCFS, and two conventionally cleaned coals for full-scale tests. Approximately, nine BCFs will be in dry microfine coal (DMPC) form, and six BCFs will be in coal-water fuel (CWF) form. Additional BCFs would be characterized during optional project supplements.

Chow, O.K.; Nsakala, N.Y.

1990-11-01

292

Orifices For Fuel-Film Cooling Of Combustion Chamber  

NASA Technical Reports Server (NTRS)

Boundary-layer film of fuel flows along wall of combustion chamber mentioned in article, "Rhenium-Foil Witness Cylinders" (NPO-18224), cooling wall and neutralizing excess of oxidizer in vicinity of wall. Enters chamber through 16 small, replaceable nozzles placed around periphery of fuel-and-oxidizer injector. Adjusted, independently of main injected flow of fuel and oxidizer, by selection of nozzle passing larger or smaller flow.

Knight, B. L.

1992-01-01

293

Spray Characterization of Gas-to-Liquid Synthetic Jet Fuels  

NASA Astrophysics Data System (ADS)

In the recent years, development of alternative jet fuels is gaining importance owing to the demand for cleaner combustion. In addition to having energy density that matches those of conventional fuels, alternate jet fuels need to possess vital qualities such as rapid atomization and vaporization, quick re-ignition at high altitude, less emission, and poses ease of handling. The fuel preparatory steps (atomization and vaporization) and mixing in a combustion chamber play a crucial role on the subsequent combustion and emission characteristics. Gas-to-Liquid (GTL) synthetic jet fuel obtained from Fischer-Tropsch synthesis has grabbed the global attention due to its cleaner combustion characteristics as a result of the absence of aromatics and sulphur. As a part of an on-going joint effort between Texas A&M at Qatar (TAMUQ), Rolls-Royce (UK), and German Aerospace Laboratory (DLR), a spray characterization experimental facility is set up at TAMUQ to study the spray characteristics of GTL fuel and highlights the influence of change in fuel composition on the spray characteristics. In this work, spray characteristics such as droplet size, velocity, and distribution of different GTL fuel blends is investigated and compared with the spray characteristics of conventional JetA1 fuel.

Kannaiyan, Kumaran; Sadr, Reza

2011-11-01

294

High-pressure combustion of binary fuel sprays  

NASA Technical Reports Server (NTRS)

The ultimate objective of this study is to obtain fundamental information relevant to combustion processes that occur in fuel sprays of practical interest at high pressures in internal combustion engines. Since practical fuels are multicomponent and derived from petroleum, the present work involves the model alkane mixture of n-heptane and n-hexadecane. Since burning droplets in sprays can interact with each other, the present work involves investigation of the effects of this interaction on flame shapes and droplet burning times. The small droplets in practical combustion chambers are not significantly influenced by buoyancy. Since such small droplets are difficult to study experimentally, the present work takes advantage of microgravity to lessen buoyancy and enable information about droplet interactions to be obtained by studying larger droplets. The results are intended to provide fundamental understanding that can be used in improving descriptions of practical spray combustion.

Mikami, Masato; Kono, Michikata; Sato, Jun'ichi; Dietrich, Daniel L.; Williams, Forman A.

1995-01-01

295

Fuel-Air Mixing and Combustion in Scramjets  

NASA Technical Reports Server (NTRS)

Activities in the area of scramjet fuel-air mixing and combustion associated with the Research and Technology Organization Working Group on Technologies for Propelled Hypersonic Flight are described. Work discussed in this paper has centered on the design of two basic experiments for studying the mixing and combustion of fuel and air in a scramjet. Simulations were conducted to aid in the design of these experiments. The experimental models were then constructed, and data were collected in the laboratory. Comparison of the data from a coaxial jet mixing experiment and a supersonic combustor experiment with a combustor code were then made and described. This work was conducted by NATO to validate combustion codes currently employed in scramjet design and to aid in the development of improved turbulence and combustion models employed by the codes.

Drummond, J. P.; Diskin, Glenn S.; Cutler, A. D.

2002-01-01

296

Brown clouds over South Asia: biomass or fossil fuel combustion?  

PubMed

Carbonaceous aerosols cause strong atmospheric heating and large surface cooling that is as important to South Asian climate forcing as greenhouse gases, yet the aerosol sources are poorly understood. Emission inventory models suggest that biofuel burning accounts for 50 to 90% of emissions, whereas the elemental composition of ambient aerosols points to fossil fuel combustion. We used radiocarbon measurements of winter monsoon aerosols from western India and the Indian Ocean to determine that biomass combustion produced two-thirds of the bulk carbonaceous aerosols, as well as one-half and two-thirds of two black carbon subfractions, respectively. These constraints show that both biomass combustion (such as residential cooking and agricultural burning) and fossil fuel combustion should be targeted to mitigate climate effects and improve air quality. PMID:19164746

Gustafsson, Orjan; Kruså, Martin; Zencak, Zdenek; Sheesley, Rebecca J; Granat, Lennart; Engström, Erik; Praveen, P S; Rao, P S P; Leck, Caroline; Rodhe, Henning

2009-01-23

297

Surrogate Model Development for Fuels for Advanced Combustion Engines  

SciTech Connect

The fuels used in internal-combustion engines are complex mixtures of a multitude of different types of hydrocarbon species. Attempting numerical simulations of combustion of real fuels with all of the hydrocarbon species included is highly unrealistic. Thus, a surrogate model approach is generally adopted, which involves choosing a few representative hydrocarbon species whose overall behavior mimics the characteristics of the target fuel. The present study proposes surrogate models for the nine fuels for advanced combustion engines (FACE) that have been developed for studying low-emission, high-efficiency advanced diesel engine concepts. The surrogate compositions for the fuels are arrived at by simulating their distillation profiles to within a maximum absolute error of 4% using a discrete multi-component (DMC) fuel model that has been incorporated in the multi-dimensional computational fluid dynamics (CFD) code, KIVA-ERC-CHEMKIN. The simulated surrogate compositions cover the range and measured concentrations of the various hydrocarbon classes present in the fuels. The fidelity of the surrogate fuel models is judged on the basis of matching their specific gravity, lower heating value, hydrogen/carbon (H/C) ratio, cetane number, and cetane index with the measured data for all nine FACE fuels.

Anand, Krishnasamy [University of Wisconsin, Madison; Ra, youngchul [University of Wisconsin, Madison; Reitz, Rolf [University of Wisconsin; Bunting, Bruce G [ORNL

2011-01-01

298

Combustion fundamentals of pyrolysis oil based fuels  

SciTech Connect

The combustion behavior of emulsions of pyrolysis oil in commercial diesel oil was studied. The emulsions were different in terms of concentration and size of the dispersed phase. The study was carried out in a single droplet combustion chamber. The size of droplets varied between 400 {mu}m and 1200 {mu}m. They were suspended to a bare thermocouple and, hence, their temperature during combustion was measured. High-speed digital shadowgraphy was used to follow droplets evolution. The main features of the droplet combustion were recognized. The general combustion behavior of emulsions is intermediate with respect to pure PO and commercial diesel oil. Emulsion droplets underwent strong swelling and microexplosion phenomena. However, under the investigated conditions, the microexplosions were ineffective in destroying droplets. The size distribution of the dispersed PO droplets in the range 3-10 {mu}m was not effective either for determining the overall thermal behavior or for the efficacy of the microexplosions. The homogeneous combustion phase resulted identical for emulsions and diesel oil despite the emulsions composition (i.e., concentration of oil, surfactant and co-surfactant, as well as the size of the oil droplets in the emulsion) and the different structure of the flame and also its time and spatial evolution. (author)

Calabria, R.; Chiariello, F.; Massoli, P. [Istituto Motori CNR, Via Marconi 8, 80125 Napoli (Italy)

2007-04-15

299

Investigation of critical burning of fuel droplets  

NASA Technical Reports Server (NTRS)

The general problem of spray combustion was investigated. The combustion of bipropellent droplets; combustion of hydrozine fuels; and combustion of sprays were studied. A model was developed to predict mean velocities and temperatures in a combusting gas jet.

Faeth, G. M.

1979-01-01

300

Generation of hypersonic liquid fuel jets accompanying self-combustion  

Microsoft Academic Search

.   Aerodynamic behavior of pulsed hypersonic light oil jets injected at 2 km\\/s and 3 km\\/s is presented. Auto-ignition and combustion\\u000a of the fuel during the injection process were visualized. The combustion around the disintegrating jet was enhanced by liquid\\u000a atomization created by the very high injection pressure as well as the interfacial instability of the hypersonic jet. The\\u000a jets

Hong-Hui Shi; Kazuyoshi Takayama

1999-01-01

301

Changes in combustion behavior of liquid fuels due to the addition of small amounts of ammonia borane or nano aluminum  

NASA Astrophysics Data System (ADS)

Both ammonia borane and nano aluminum as additives to liquid fuels are investigated. Both fundamental droplet combustion experiments and experiments using an unstable liquid rocket combustor are used to study the effects these additives on the combustion behavior. The liquid fuels consist of ethanol and JP-8. The droplet experiments consist of both visual and OH high speed planar laser-induced fluorescence measurements. Simple combustion models are incorporated as well to provide further understanding. It is found that ammonia borane increases the regression rate of a single ethanol droplet. Evidence indicates that hydrogen gas is released throughout the combustion process of the droplet and influences the combustion behavior notably. Laser diagnostics indicate that changes in flame structure occur. The other components of ammonia borane affect the combustion behavior of the droplet, especially near the end of the droplet lifetime, causing the droplet to shatter. Nano aluminum has very little impact on the combustion behavior of single fuel droplets of JP-8 and ethanol. Nano aluminum is observed to combust only when a surfactant, Neodol, is present which produces gas generation and bubble formation within the droplet. Combustor experiments show similar trends as the droplet combustion experiments. Ammonia borane has a notable impact on the combustion stability of the system allowing it to be unstable for more combustor geometries. It is shown that ammonia borane addition produces a bimodal unsteady energy release within the combustor while the neat fuel does not. This combustion behavior allows for the increased amount of unstable combustor geometries. Nano aluminum has a small impact on the combustion stability of the system causing pressure oscillations to increase.

Pfeil, Mark A.

302

MCO combustible gas management leak test acceptance criteria  

SciTech Connect

Existing leak test acceptance criteria for mechanically sealed and weld sealed multi-canister overpacks (MCO) were evaluated to ensure that MCOs can be handled and stored in stagnant air without compromising the Spent Nuclear Fuel Project's overall strategy to prevent accumulation of combustible gas mixtures within MCO's or within their surroundings. The document concludes that the integrated leak test acceptance criteria for mechanically sealed and weld sealed MCOs (1 x 10{sup -5} std cc/sec and 1 x 10{sup -7} std cc/sec, respectively) are adequate to meet all current and foreseeable needs of the project, including capability to demonstrate compliance with the NFPA 60 Paragraph 3-3 requirement to maintain hydrogen concentrations [within the air atmosphere CSB tubes] t or below 1 vol% (i.e., at or below 25% of the LFL).

SHERRELL, D.L.

1999-05-11

303

Removal of mercury from coal-combustion flue-gas  

SciTech Connect

Combustion sources, including those using coal for fuel, contribute a significant fraction of total anthropogenic mercury emissions. Recent field studies have shown that current flue-gas cleanup (FGC) systems are relatively ineffective in controlling elemental mercury, which is a major component of the mercury emissions for many systems. Research at Argonne National Laboratory has been focused on techniques to enhance the capture of elemental mercury in existing FGC systems. For dry processes, these studies have included evaluation of activated carbons and investigation of sorbents based upon chemical pretreatment of low-cost mineral substrates. To enhance the ability of wet scrubbers to capture mercury, the studies have looked at the effects of improved mass transfer through both mechanical and chemical means, as well as the conversion of elemental mercury into more soluble species that can be easily absorbed.

Livengood, C.D.; Huang, H.S.; Mendelsohn, M.H.; Wu, J.M.

1995-12-01

304

Straw pellets as fuel in biomass combustion units  

SciTech Connect

In order to estimate the suitability of straw pellets as fuel in small combustion units, the Danish Technological Institute accomplished a project including a number of combustion tests in the energy laboratory. The project was part of the effort to reduce the use of fuel oil. The aim of the project was primarily to test straw pellets in small combustion units, including the following: ash/slag conditions when burning straw pellets; emission conditions; other operational consequences; and necessary work performance when using straw pellets. Five types of straw and wood pellets made with different binders and antislag agents were tested as fuel in five different types of boilers in test firings at 50% and 100% nominal boiler output.

Andreasen, P.; Larsen, M.G. [Danish Technological Inst., Aarhus (Denmark)

1996-12-31

305

Fundamental characterization of alternate fuel effects in continuous combustion systems. Summary technical progress report, August 15, 1978-January 31, 1980  

SciTech Connect

The overall objective of this contract is to assist in the development of fuel-flexible combustion systems for gas turbines as well as Rankine and Stirling cycle engines. The primary emphasis of the program is on liquid hydrocarbons produced from non-petroleum resources. Fuel-flexible combustion systems will provide for more rapid transition of these alternative fuels into important future energy utilization centers (especially utility power generation with the combined cycle gas turbine). The specific technical objectives of the program are: (a) develop an improved understanding of relationships between alternative fuel properties and continuous combustion system effects, and (b) provide analytical modeling/correlation capabilities to be used as design aids for development of fuel-tolerant combustion systems. This is the second major report of the program. Key experimental findings during this reporting period concern stirred combustor soot production during operation at controlled temperature conditions, soot production as a function of combustor residence time, an improved measurement technique for total hydrocarbons and initial stirred combustor results of fuel nitrogen conversion. While the results to be presented concern a stirred combustor which utilizes premixed fuel vapor/oxidant mixtures, a new combustor which combusts liquid fuel injected into the reactor as a spray has been developed and will be described. Analytical program progress includes the development of new quasiglobal models of soot formation and assessment of needs for other submodel development.

Blazowski, W.S.; Edelman, R.B.; Wong, E.

1980-02-27

306

Reduced Gravity Studies of Soret Transport Effects in Liquid Fuel Combustion  

NASA Technical Reports Server (NTRS)

Soret transport, which is mass transport driven by thermal gradients, can be important in practical flames as well as laboratory flames by influencing transport of low molecular weight species (e.g., monatomic and diatomic hydrogen). In addition, gas-phase Soret transport of high molecular weight fuel species that are present in practical liquid fuels (e.g., octane or methanol) can be significant in practical flames (Rosner et al., 2000; Dakhlia et al., 2002) and in high pressure droplet evaporation (Curtis and Farrell, 1992), and it has also been shown that Soret transport effects can be important in determining oxygen diffusion rates in certain classes of microgravity droplet combustion experiments (Aharon and Shaw, 1998). It is thus useful to obtain information on flames under conditions where Soret effects can be clearly observed. This research is concerned with investigating effects of Soret transport on combustion of liquid fuels, in particular liquid fuel droplets. Reduced-gravity is employed to provide an ideal (spherically-symmetrical) experimental model with which to investigate effects of Soret transport on combustion. The research will involve performing reduced-gravity experiments on combustion of liquid fuel droplets in environments where Soret effects significantly influence transport of fuel and oxygen to flame zones. Experiments will also be performed where Soret effects are not expected to be important. Droplets initially in the 0.5 to 1 mm size range will be burned. Data will be obtained on influences of Soret transport on combustion characteristics (e.g., droplet burning rates, droplet lifetimes, gas-phase extinction, and transient flame behaviors) under simplified geometrical conditions that are most amenable to theoretical modeling (i.e., spherical symmetry). The experiments will be compared with existing theoretical models as well as new models that will be developed. Normal gravity experiments will also be performed.

Shaw, Benjamin D.

2004-01-01

307

Evaluation of advanced combustion concepts for dry NO sub x suppression with coal-derived, gaseous fuels  

NASA Technical Reports Server (NTRS)

The emissions performance of a rich lean combustor (developed for liquid fuels) was determined for combustion of simulated coal gases ranging in heating value from 167 to 244 Btu/scf (7.0 to 10.3 MJ/NCM). The 244 Btu/scf gas is typical of the product gas from an oxygen blown gasifier, while the 167 Btu/scf gas is similar to that from an air blown gasifier. NOx performance of the rich lean combustor did not meet program goals with the 244 Btu/scf gas because of high thermal NOx, similar to levels expected from conventional lean burning combustors. The NOx emissions are attributed to inadequate fuel air mixing in the rich stage resulting from the design of the large central fuel nozzle delivering 71% of the total gas flow. NOx yield from ammonia injected into the fuel gas decreased rapidly with increasing ammonia level, and is projected to be less than 10% at NH3 levels of 0.5% or higher. NOx generation from NH3 is significant at ammonia concentrations significantly less than 0.5%. These levels may occur depending on fuel gas cleanup system design. CO emissions, combustion efficiency, smoke and other operational performance parameters were satisfactory. A test was completed with a catalytic combustor concept with petroleum distillate fuel. Reactor stage NOx emissions were low (1.4g NOx/kg fuel). CO emissions and combustion efficiency were satisfactory. Airflow split instabilities occurred which eventually led to test termination.

Beebe, K. W.; Symonds, R. A.; Notardonato, J. J.

1982-01-01

308

Comparison of exhaust emissions and their mutagenicity from the combustion of biodiesel, vegetable oil, gas-to-liquid and petrodiesel fuels  

Microsoft Academic Search

Efforts are under way to reduce diesel engine emissions (DEE) and their content of carcinogenic and mutagenic polycyclic aromatic hydrocarbons (PAH). Previously, we observed reduced PAH emissions and DEE mutagenicity caused by reformulated or newly developed fuels. The use of rapeseed oil as diesel engine fuel is growing in German transportation businesses and agriculture. We now compared the mutagenic effects

Jürgen Krahl; Gerhard Knothe; Axel Munack; Yvonne Ruschel; Olaf Schröder; Ernst Hallier; Götz Westphal; Jürgen Bünger

2009-01-01

309

Two-stage combustion for reducing pollutant emissions from gas turbine combustors  

NASA Technical Reports Server (NTRS)

Combustion and emission results are presented for a premix combustor fueled with admixtures of JP5 with neat H2 and of JP5 with simulated partial-oxidation product gas. The combustor was operated with inlet-air state conditions typical of cruise power for high performance aviation engines. Ultralow NOx, CO and HC emissions and extended lean burning limits were achieved simultaneously. Laboratory scale studies of the non-catalyzed rich-burning characteristics of several paraffin-series hydrocarbon fuels and of JP5 showed sooting limits at equivalence ratios of about 2.0 and that in order to achieve very rich sootless burning it is necessary to premix the reactants thoroughly and to use high levels of air preheat. The application of two-stage combustion for the reduction of fuel NOx was reviewed. An experimental combustor designed and constructed for two-stage combustion experiments is described.

Clayton, R. M.; Lewis, D. H.

1981-01-01

310

Development and integration of a scalable low NOx combustion chamber for a hydrogen-fueled aerogas turbine  

NASA Astrophysics Data System (ADS)

The usage of alternative fuels in aircraft industry plays an important role of current aero engine research and development processes. The micromix burning principle allows a secure and low NOx combustion of gaseous hydrogen. The combustion principle is based on the fluid phenomenon of jet in cross flow and achieves a significant lowering in NOx formation by using multiple miniaturized flames. The paper highlights the development and the integration of a combustion chamber, based on the micromix combustion principle, into an Auxiliary Power Unit (APU) GTCP 36-300 with regard to the necessary modifications on the gas turbine and on the engine controller.

Boerner, S.; Funke, H. H.-W.; Hendrick, P.; Recker, E.; Elsing, R.

2013-03-01

311

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

PubMed

Ventilation air methane (VAM) accounts for 60-80% of the total emissions from 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. PMID:18505001

You, Changfu; Xu, Xuchang

2008-04-01

312

Development of high temperature air combustion technology in pulverized fossil fuel fired boilers  

SciTech Connect

High temperature air combustion (HTAC) is a promising technology for energy saving, flame stability enhancement and NOx emission reduction. In a conventional HTAC system, the combustion air is highly preheated by using the recuperative or regenerative heat exchangers. However, such a preheating process is difficult to implement for pulverized fossil fuel fired boilers. In this paper, an alternative approach is proposed. In the proposed HTAC system, a special burner, named PRP burner is introduced to fulfill the preheating process. The PRP burner has a preheating chamber with one end connected with the primary air and the other end opened to the furnace. Inside the chamber, gas recirculation is effectively established such that hot flue gases in the furnace can be introduced. Combustible mixture instead of combustion air is highly preheated by the PRP burner. A series of experiments have been conducted in an industrial scale test facility, burning low volatile petroleum coke and an anthracite coal. Stable combustion was established for burning pure petroleum coke and anthracite coal, respectively. Inside the preheating chamber, the combustible mixture was rapidly heated up to a high temperature level close to that of the hot secondary air used in the conventional HTAC system. The rapid heating of the combustible mixture in the chamber facilitates pyrolysis, volatile matter release processes for the fuel particles, suppressing ignition delay and enhancing combustion stability. Moreover, compared with the results measured in the same facility but with a conventional low NOx burner, NOx concentration at the furnace exit was at the same level when petroleum coke was burnt and 50% less when anthracite was burnt. Practicability of the HTAC technology using the proposed approach was confirmed for efficiently and cleanly burning fossil fuels. 16 refs., 10 figs., 1 tab.

Hai Zhang; Guangxi Yue; Junfu Lu; Zhen Jia; Jiangxiong Mao; Toshiro Fujimori; Toshiyuki Suko; Takashi Kiga [Tsinghua University, Beijing (China). Department of Thermal Engineering

2007-07-01

313

Study on Combustion and Emission Characteristics of a DI Diesel Engine Fueled with Blends of Biodiesel  

Microsoft Academic Search

The combustion and emission of a direct injection diesel engine fueled with blends of biodiesel were investigated. The characteristics of combustion and emission with deferent biodiesel\\/diesel blend ratio in a diesel engine were analyzed. The results showed that for the same engine operating condition, compared to the diesel fuel, the combustion process was improved and better combustion characteristics could be

Cheng Xiao-bei; Ju Hongling; Kong Peng; Pan Li

2007-01-01

314

Comparing the greenhouse gas emissions from three alternative waste combustion concepts.  

PubMed

Three alternative condensing mode power and combined heat and power (CHP) waste-to-energy concepts were compared in terms of their impacts on the greenhouse gas (GHG) emissions from a heat and power generation system. The concepts included (i) grate, (ii) bubbling fluidised bed (BFB) and (iii) circulating fluidised bed (CFB) combustion of waste. The BFB and CFB take advantage of advanced combustion technology which enabled them to reach electric efficiency up to 35% and 41% in condensing mode, respectively, whereas 28% (based on the lower heating value) was applied for the grate fired unit. A simple energy system model was applied in calculating the GHG emissions in different scenarios where coal or natural gas was substituted in power generation and mix of fuel oil and natural gas in heat generation by waste combustion. Landfilling and waste transportation were not considered in the model. GHG emissions were reduced significantly in all of the considered scenarios where the waste combustion concepts substituted coal based power generation. With the exception of condensing mode grate incinerator the different waste combustion scenarios resulted approximately in 1 Mton of fossil CO(2)-eq. emission reduction per 1 Mton of municipal solid waste (MSW) incinerated. When natural gas based power generation was substituted by electricity from the waste combustion significant GHG emission reductions were not achieved. PMID:22079250

Vainikka, Pasi; Tsupari, Eemeli; Sipilä, Kai; Hupa, Mikko

2012-03-01

315

Combustion chambers of gas-turbine plants - Heat transfer  

Microsoft Academic Search

Results of studies concerned with the convective and radiation heat transfer in the combustion chambers of gas turbines are examined. In particular, the existing methods for cooling flame tubes are analyzed, and heat transfer calculations are carried out for highly augmented combustion chambers. A method is also presented for calculating complex heat transfer in the flame zone for various types

A. V. Sudarev; V. I. Antonovskii

1985-01-01

316

A comprehensive combustion model for biodiesel-fueled engine simulations  

NASA Astrophysics Data System (ADS)

Engine models for alternative fuels are available, but few are comprehensive, well-validated models that include accurate physical property data as well as a detailed description of the fuel chemistry. In this work, a comprehensive biodiesel combustion model was created for use in multi-dimensional engine simulations, specifically the KIVA3v R2 code. The model incorporates realistic physical properties in a vaporization model developed for multi-component fuel sprays and applies an improved mechanism for biodiesel combustion chemistry. A reduced mechanism was generated from the methyl decanoate (MD) and methyl-9-decenoate (MD9D) mechanism developed at Lawrence Livermore National Laboratory. It was combined with a multi-component mechanism to include n-heptane in the fuel chemistry. The biodiesel chemistry was represented using a combination of MD, MD9D and n-heptane, which varied for a given fuel source. The reduced mechanism, which contained 63 species, accurately predicted ignition delay times of the detailed mechanism over a range of engine-specific operating conditions. Physical property data for the five methyl ester components of biodiesel were added to the KIVA library. Spray simulations were performed to ensure that the models adequately reproduce liquid penetration observed in biodiesel spray experiments. Fuel composition impacted liquid length as expected, with saturated species vaporizing more and penetrating less. Distillation curves were created to ensure the fuel vaporization process was comparable to available data. Engine validation was performed against a low-speed, high-load, conventional combustion experiments and the model was able to predict the performance and NOx formation seen in the experiment. High-speed, low-load, low-temperature combustion conditions were also modeled, and the emissions (HC, CO, NOx) and fuel consumption were well-predicted for a sweep of injection timings. Finally, comparisons were made between the results of biodiesel composition (palm vs. soy) and fuel blends (neat vs. B20). The model effectively reproduced the trends observed in the experiments.

Brakora, Jessica L.

317

Ammonia chemistry in oxy-fuel combustion of methane  

SciTech Connect

The oxidation of NH{sub 3} during oxy-fuel combustion of methane, i.e., at high [CO{sub 2}], has been studied in a flow reactor. The experiments covered stoichiometries ranging from fuel rich to very fuel lean and temperatures from 973 to 1773 K. The results have been interpreted in terms of an updated detailed chemical kinetic model. A high CO{sub 2} level enhanced formation of NO under reducing conditions while it inhibited NO under stoichiometric and lean conditions. The detailed chemical kinetic model captured fairly well all the experimental trends. According to the present study, the enhanced CO concentrations and alteration in the amount and partitioning of O/H radicals, rather than direct reactions between N-radicals and CO{sub 2}, are responsible for the effect of a high CO{sub 2} concentration on ammonia conversion. When CO{sub 2} is present as a bulk gas, formation of NO is facilitated by the increased OH/H ratio. Besides, the high CO levels enhance HNCO formation through NH{sub 2}+CO. However, reactions NH{sub 2}+ O to form HNO and NH{sub 2}+H to form NH are inhibited due to the reduced concentration of O and H radicals. Instead reactions of NH{sub 2} with species from the hydrocarbon/methylamine pool preserve reactive nitrogen as reduced species. These reactions reduce the NH{sub 2} availability to form NO by other pathways like via HNO or NH and increase the probability of forming N{sub 2} instead of NO. (author)

Mendiara, Teresa; Glarborg, Peter [Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Lyngby (Denmark)

2009-10-15

318

10 CFR 50.44 - Combustible gas control for nuclear power reactors.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Combustible gas control for nuclear power reactors. 50.44 Section... § 50.44 Combustible gas control for nuclear power reactors. (a) Definitions...concentration of combustible gases in any part of the...

2009-01-01

319

NITROUS OXIDE EMISSIONS FROM FOSSIL FUEL COMBUSTION  

EPA Science Inventory

The role of coal combustion as a significant global source of nitrous oxide (N2O) emissions was reexamined through on-line emission measurements from six pulverized-coal-fired utility boilers and from laboratory and pilot-scale combustors. The full-scale utility boilers yielded d...

320

NiO\\/NiAl 2O 4 oxygen carriers prepared by sol-gel for chemical-looping combustion fueled by gas  

Microsoft Academic Search

Chemical-looping combustion with inherent CO2 enrichment depends on the high-powered oxygen carriers. Ni(NO3)2 and Al(OC3H7)3 are selected as the main raw materials to prepare sol-gel-derived NiO\\/NiAl2O4, by matching the appropriate experimental parameters. The oxygen carrier with a mass content of 60% NiO, a sintering temperature of 1300°C, and a sintering time of 6 h performs comparatively good physicochemical properties. The

Hai-bo ZHAO; Li-ming LIU; Di XU; Chu-guang ZHENG; Guo-jun LIU; Lin-lin JIANG

2008-01-01

321

Combustion in a bomb with a fuel-injection system  

NASA Technical Reports Server (NTRS)

Fuel injected into a spherical bomb filled with air at a desired density and temperature could be ignited with a spark a few thousandths of a second after injection, an interval comparable with the ignition lag in fuel-injection engines. The effect of several variables on the extent and rate of combustion was investigated: time intervals between injection and ignition of fuel of 0.003 to 0.06 second and one of 5 minutes; initial air temperatures of 100 degrees C. to 250 degrees C.; initial air densities equivalent to 5, 10, and 15 absolute atmospheres pressure at 100 degrees C.; and air-fuel ratios of 5 to 25.

Cohn, Mildred; Spencer, Robert C

1935-01-01

322

Combustion in a Bomb with a Fuel-Injection System  

NASA Technical Reports Server (NTRS)

Fuel injected into a spherical bomb filled with air at a desired density and temperature could be ignited with a spark a few thousandths of a second after injection, an interval comparable with the ignition lag in fuel-injection engines. The effect of several variables on the extent and rate of combustion was investigated: time intervals between injection and ignition of fuel of 0.003 to 0.06 second and one of 5 minutes; initial air temperatures of 100 degrees C. to 250 degrees C.; initial air densities equivalent to 5, 10, and 15 absolute atmospheres pressure at 100 degrees C.; and air-fuel ratios of 5 to 25.

Cohn, Mildred; Spencer, Robert C

1935-01-01

323

Fuel cell gas management system  

DOEpatents

A fuel cell gas management system including a cathode humidification system for transferring latent and sensible heat from an exhaust stream to the cathode inlet stream of the fuel cell; an anode humidity retention system for maintaining the total enthalpy of the anode stream exiting the fuel cell equal to the total enthalpy of the anode inlet stream; and a cooling water management system having segregated deionized water and cooling water loops interconnected by means of a brazed plate heat exchanger.

DuBose, Ronald Arthur (Marietta, GA)

2000-01-11

324

NASA broad-specification fuels combustion technology program  

NASA Technical Reports Server (NTRS)

The NASA Broad-Specification Fuels Combustion Technology Program was initiated in response to concerns that the supply of high-quality petroleum middle distillates for jet fuel, abundant in the past, would diminish in availability toward the end of the century. The specific program objective is to evolve the combustion system technology required to use fuels with moderate ranges of broadened properties in the engines used on commercial jet aircraft. The first phase of the program, in which effects of the use of broadened-properties fuels were identified and technology with the potential to offset these effects was also identified, has been completed. The second phase, in which the technology identified in Phase 1 is being refined, will be completed within the next three months.

Fear, J. S.

1984-01-01

325

Two-stage slagging combustor design for a coal-fueled industrial gas turbine  

Microsoft Academic Search

This paper reports on a full-size combustor for a coal-fueled industrial gas turbine engine which has been designed and fabricated. The design is based on extensive work completed through one-tenth scale combustion tests. Testing of the combustion hardware will be completed with a high pressure air supply in a combustion test facility before the components are integrated with the gas

L. H. Cawell; R. T. LeCren; C. E. Tenbrook

1992-01-01

326

New Trends in Combustion Research for Gas Turbine Engines.  

National Technical Information Service (NTIS)

Research on combustion is being conducted to provide improved analytical models of complex flow and chemical reaction processes which occur in the combustor of gas turbine engines, in order to enable engine manufacturers to reduce the development time of ...

E. J. Mularz

1983-01-01

327

ShockTube Combustion of High Density Hydrocarbon Fuels  

Microsoft Academic Search

Shock-tube techniques have been used to determine rates of carbon dioxide production in shock-wave heated mixtures of oxygen and hydrogenated dimers of bicycloheptadiene, components of the high density fuel RJ-S. Reaction profiles generated by this method have demonstrated that the combustion rate of the hydrocarbon vapors increases with fuel and oxygen concentration, but is not affected by the total pressure

J. M. BRUPBACHER; M. T. McCALL; M. McCARTY Jr

1978-01-01

328

Hybrid rocket fuel combustion and regression rate study  

NASA Technical Reports Server (NTRS)

The objectives of this study are to develop hybrid fuels (1) with higher regression rates and reduced dependence on fuel grain geometry and (2) that maximize potential specific impulse using low-cost materials. A hybrid slab window motor system was developed to screen candidate fuels - their combustion behavior and regression rate. Combustion behavior diagnostics consisted of video and high speed motion pictures coverage. The mean fuel regression rates were determined by before and after measurements of the fuel slabs. The fuel for this initial investigation consisted of hydroxyl-terminated polybutadiene binder with coal and aluminum fillers. At low oxidizer flux levels (and corresponding fuel regression rates) the filled-binder fuels burn in a layered fashion, forming an aluminum containing binder/coal surface melt that, in turn, forms into filigrees or flakes that are stripped off by the crossflow. This melt process appears to diminish with increasing oxidizer flux level. Heat transfer by radiation is a significant contributor, producing the desired increase in magnitude and reduction in flow dependency (power law exponent) of the fuel regression rate.

Strand, L. D.; Ray, R. L.; Anderson, F. A.; Cohen, N. S.

1992-01-01

329

Hexaaluminate Combustion Catalysts for Fuel Cell Fuel Reformers.  

National Technical Information Service (NTIS)

Fuel cells may offer significant advantages over conventional diesel generator sets for mobile military electric power applications. Fuel cells can provide quiet, flexible, and fuel-efficient operation, making them suitable for use in 'stealth' vehicles o...

A. H. Shaaban F. H. Holcomb F. S. Thomas M. J. Binder T. J. Campbell

2004-01-01

330

Co-combustion: Burning biomass, fossil fuels together simplifies waste disposal, cuts fuel cost  

Microsoft Academic Search

Getting energy from biomass has introduced a new dimension in combustion systems. This report explores the state of the art of multifuel combustion, describes how existing firing systems can be optimized or refined for disparate fuels, outlines new firing systems-fluidized-bed combustors and gasifiers-that can be applied as well.

Makansi

1987-01-01

331

Characterization of fuels for atmospheric fluidized bed combustion  

SciTech Connect

The Electric Power Research Institute (EPRI) has sponsored a fuels characterization program for the past several years with the intention of assisting utilities and boiler manufacturers in evaluating fuel quality impact on atmospheric fluidized bed combustion (AFBC) performance. The goal has been to provide an improved framework for making fuel switching decisions and consolidating operating experience. Results from this program include a set of bench-scale testing procedures, a fuel characterization data base, and a performance simulation model that links fuel characteristics to combustion performance. This paper reviews the major results of the fuels characterization program. The testing procedures, data base, and performance simulation models are briefly described and their application illustrated with examples. Performance predictions for the B W 1-ft{sup 2} bench-scale AFBC and the Tennessee Valley Authority (TVA) 20 MW(e) AFBC Pilot Plant are compared with actual test data. The relationship of coal rank to combustion is discussed. 11 refs., 12 figs., 5 tabs.

Daw, C.S. (Oak Ridge National Lab., TN (USA)); Rowley, D.R.; Perna, M.A. (Babcock and Wilcox Co., Alliance, OH (USA). Research Center); Stallings, J.W. (Electric Power Research Inst., Palo Alto, CA (USA)); Divilio, R.J. (Combustion Systems, Inc., Silver Spring, MD (USA))

1990-01-01

332

On-line measurement of nitrous oxide from combustion sources by automated gas chromatography. Rept. for Jun 90-Jun 92  

SciTech Connect

The paper discusses on-line measurement of nitrous oxide (N2O) from combustion sources by automated gas chromatography. Fossil fuel combustion is suspected of contributing to measured increases in the ambient concentrations of N2O. Characterization of N2O emissions from fossil fuel combustion and associated pollution control systems has been hindered by the generation of N2O from nitrogen oxides, sulfur dioxide, and moisture present in the sample vessel while samples await analysis. To truly assess N2O emissions from fossil fuel combustion, a real-time or near real-time measurement technique is required. To accomplish this, a gas chromatograph equipped with an electron capture detector was configured and automated. The system is capable of detection levels below ambient concentrations and a practical quantifying range of 0.1 to 200 ppm. A precolumn backflushing system negates the effects of interferents present in fossil fuel combustion emissions. The automated system, capable of one on-line measurement every 8 minutes, has been used to evaluate N2O emissions from a variety of combustion sources, fuels, and post-combustion pollution control techniques.

Ryan, J.V.; Linak, W.P.

1992-01-01

333

Fuel Chemistry And Combustion Distribution Effects On Rocket Engine Combustion Stability.  

National Technical Information Service (NTIS)

The goal of the project was to understand how changes in the rate of energy addition can be used to alter the combustion instability characteristics of liquid rocket engines. Fuels with increased energy, either due to higher heats of formation or energeti...

S. D. Heister S. S. Son W. E. Anderson

2013-01-01

334

Brown Clouds over South Asia: Biomass or Fossil Fuel Combustion?  

Microsoft Academic Search

Carbonaceous aerosols cause strong atmospheric heating and large surface cooling that is as important to South Asian climate forcing as greenhouse gases, yet the aerosol sources are poorly understood. Emission inventory models suggest that biofuel burning accounts for 50 to 90 % of emissions, whereas the elemental composition of ambient aerosols points to fossil fuel combustion. We used radiocarbon measurements

Örjan Gustafsson; Martin Kruså; Zdenek Zencak; Rebecca J. Sheesley; Lennart Granat; Erik Engström; P. S. Praveen; P. S. P. Rao; Caroline Leck; Henning Rodhe

2009-01-01

335

Sedimentary records of carbonaceous particles from fossil fuel combustion  

Microsoft Academic Search

Carbonaceous particles produced by fossil fuel combustion can be found in considerable amounts in recent lake sediments. As these particles contain elemental carbon they are resistant to chemical decomposition and therefore both well preserved in sediments and possible to quantify. Sediment samples can be oxidized with H2O2 and digested with HF without the particles being destroyed. The pioneers in studying

Maria Wik; Ingemar Renberg; Judi Darley

1986-01-01

336

Effects of fuel and additives on combustion chamber deposits  

Microsoft Academic Search

The effects of gasoline composition, as represented in typical regular and premium unleaded gasolines and fuel additives, on Combustion Chamber Deposits (CCD) were investigated in BMW and Ford tests. In addition, the influences of engine lubricant oil and ethanol oxygenate on CCD were examined in Ford 2.3L engine dynamometer tests. Also, additive effects of packages based on mineral oil fluidizers

M. M. Jackson; S. B. Pocinki

1994-01-01

337

Combustion of refuse-derived fuel in a fluidised bed  

Microsoft Academic Search

As a medium to maximise the resources recovery from municipal solid waste, refuse-derived fuel (RDF) is considered as a priority solution in industrialised countries. RDF is a value added material with a higher calorific value and a homogeneous particle size. The main objective of this study was to investigate the RDF combustion characteristics and the associated pollutant emissions in a

Francisco D. Hernandez-Atonal; Changkook Ryu; Vida N. Sharifi; Jim Swithenbank

2007-01-01

338

Solid Surface Combustion Experiment: Thick Fuel Results  

NASA Technical Reports Server (NTRS)

The results of experiments for spread over polymethylmethacrylate, PMMA, samples in the microgravity environment of the Space Shuttle are described. The results are coupled with modelling in an effort to describe the physics of the spread process for thick fuels in a quiescent, microgravity environment and uncover differences between thin and thick fuels. A quenching phenomenon not present for thin fuels is delineated, namely the fact that for thick fuels the possibility exists that, absent an opposing flow of sufficient strength to press the flame close enough to the fuel surface to allow the heated layer in the solid to develop, the heated layer fails to become 'fully developed.' The result is that the flame slows, which in turn causes an increase in the relative radiative loss from the flame, leading eventually to extinction. This potential inability of a thick fuel to develop a steady spread rate is not present for a thin fuel because the heated layer is the fuel thickness, which reaches a uniform temperature across the thickness relatively rapidly.

Altenkirch, Robert A.; Bhattacharjee, Subrata; West, Jeff; Tang, Lin; Sacksteder, Kurt; Delichatsios, Michael A.

1997-01-01

339

Combustion of liquid fuels in diesel engine  

NASA Technical Reports Server (NTRS)

Hitherto, definite specifications have always been made for fuel oils and they have been classified as more or less good or non-utilizable. The present aim, however, is to build Diesel engines capable of using even the poorest liquid fuels and especially the waste products of the oil industry, without special chemical or physical preparation.

Alt, Otto

1924-01-01

340

DOE Project 18546, AOP Task 1.1, Fuel Effects on Advanced Combustion Engines.  

National Technical Information Service (NTIS)

Research in 2011 was focused on diesel range fuels and diesel combustion and fuels evaluated in 2011 included a series of oxygenated biofuels fuels from University of Maine, oxygenated fuel compounds representing materials which could be made from sewage,...

B. G. Bunting M. Bunce

2012-01-01

341

Low NOx heavy fuel combustor concept program. Phase 1: Combustion technology generation  

NASA Astrophysics Data System (ADS)

The viability of low emission nitrogen oxide (NOx) gas turbine combustors for industrial and utility application. Thirteen different concepts were evolved and most were tested. Acceptable performance was demonstrated for four of the combustors using ERBS fuel and ultralow NOx emissions were obtained for lean catalytic combustion. Residual oil and coal derived liquids containing fuel bound nitrogen (FBN) were also used at test fuels, and it was shown that staged rich/lean combustion was effective in minimizing the conversion of FBN to NOx. The rich/lean concept was tested with both modular and integral combustors. While the ceramic lined modular configuration produced the best results, the advantages of the all metal integral burners make them candidates for future development. An example of scaling the laboratory sized combustor to a 100 MW size engine is included in the report as are recommendations for future work.

Lew, H. G.; Carl, D. R.; Vermes, G.; Dezubay, E. A.; Schwab, J. A.; Prothroe, D.

1981-10-01

342

Low NOx heavy fuel combustor concept program. Phase 1: Combustion technology generation  

NASA Technical Reports Server (NTRS)

The viability of low emission nitrogen oxide (NOx) gas turbine combustors for industrial and utility application. Thirteen different concepts were evolved and most were tested. Acceptable performance was demonstrated for four of the combustors using ERBS fuel and ultralow NOx emissions were obtained for lean catalytic combustion. Residual oil and coal derived liquids containing fuel bound nitrogen (FBN) were also used at test fuels, and it was shown that staged rich/lean combustion was effective in minimizing the conversion of FBN to NOx. The rich/lean concept was tested with both modular and integral combustors. While the ceramic lined modular configuration produced the best results, the advantages of the all metal integral burners make them candidates for future development. An example of scaling the laboratory sized combustor to a 100 MW size engine is included in the report as are recommendations for future work.

Lew, H. G.; Carl, D. R.; Vermes, G.; Dezubay, E. A.; Schwab, J. A.; Prothroe, D.

1981-01-01

343

Improving the Carbon Dioxide Emission Estimates from the Combustion of Fossil Fuels in California and Disaggregated Estimate of Energy-Related Carbon Dioxide for California.  

National Technical Information Service (NTIS)

Central to any study of climate change is the development of an emission inventory that identifies and quantifies the State's primary anthropoganic sources and sinks of greenhouse gas (GHG) emissions. CO2 emissions from fossil fuel combustion accounted fo...

2008-01-01

344

Leading Studies of the Staged Combustion Hybrid Rocket  

Microsoft Academic Search

The staged combustion hybrid rocket is under development by our research group since 1999. This hybrid rocket engine consists of two combustion chambers. The primary combustion chamber is the fuel tank itself filled with granular solid fuels. The fuel rich gas generated by the first stage combustion flows into the secondary combustion chamber, which is located in the bottom of

Ryojiro Akiba; Yoshinori Aoki; Seiyu Kayuta; Atushi Fujii; Harunori Nagata; Shin Satori

2003-01-01

345

A fundamental study on the control of the HCCI combustion and emissions by fuel design concept combined with controllable EGR. Part 2. Effect of operating conditions and EGR on HCCI combustion  

Microsoft Academic Search

In Part 1, the effects of octane number of primary reference fuels and equivalence ration on combustion characteristics of a single-cylinder HCCI engine were studied. In this part, the influence of exhaust gas recirculation (EGR) rate, intake charge temperature, coolant temperature, and engine speed on the HCCI combustion characteristics and its emissions were evaluated. The experimental results indicate that the

Xing-Cai Lü; Wei Chen; Zhen Huang

2005-01-01

346

Relationship of fuel size and spacing to combustion characteristics of laboratory fuel cribs  

SciTech Connect

This paper reports on flaming combustion in cribs of large woody fuels, thickness 5 cm or greater, that is not sustained when fuel spacing ratio, fuel edge-to-edge separation distance to fuel thickness, is greater than 3:1. The flame length associated with the large-fuel burning rate was found to drop rapidly when the large-fuel spacing ratio increases beyond 2.23:1. This supports the critical spacing assigned in the large-fuel subroutine burnout of Albini's fire modeling program.

Anderson, H.E.

1990-01-01

347

Development of the Utilization of Combustible Gas Produced in Existing Sanitary Landfills. Investigation of Effects of Air Inclusion.  

National Technical Information Service (NTIS)

A combustible gas mixture composed of methane and carbon dioxide is generated in municipal solid waste landfills. A practical consequence of the collection of this fuel gas is the inclusion of some air in the collected product. This report discusses the e...

1981-01-01

348

Development of the Utilization of Combustible Gas Produced in Existing Sanitary Landfills: Investigation of Effects of Air Inclusion.  

National Technical Information Service (NTIS)

A combustible gas mixture composed of methane and carbon dioxide is generated in municipal solid waste landfills. A practical consequence of the collection of this fuel gas is the inclusion of some air in the collected product. The effects of such include...

1983-01-01

349

A test device for premixed gas turbine combustion oscillations  

SciTech Connect

This report discusses design and operation of a single-nozzle test combustor for studying lean, premixed combustion oscillations from gas turbine fuel nozzles. It was used to study oscillations from a prototype fuel nozzle that produced oscillations during testing in a commercial engine. Similar, but not identical, oscillations were recorded in the test device. Basic requirements of the device design were that the flame geometry be maintained and acoustic losses be minimized; this was achieved by using a Helmholtz resonator as the combustor geometry. Surprisingly, the combustor oscillated strongly at several frequencies, without modification of the resonator. Brief survey of operating conditions suggests that it may be helpful to characterize oscillating behavior in terms of reference velocity and inlet air temperature with the rig backpressure playing a smaller role. The preliminary results do not guarantee that the single-nozzle test device will reproduce arbitrary oscillations that occur on a complete engine test. Nozzle/nozzle interactions may complicate the response, and oscillations controlled by acoustic velocities transverse to the nozzle axis may not be reproduced in a test device that relies on a bulk Helmholtz mode. Nevertheless, some oscillations can be reproduced, and the single-nozzle test device allows both active and passive control strategies to be tested relatively inexpensively.

Richards, G.A.; Gemmen, R.S.; Yip, M.J.

1996-03-01

350

Numerical analysis of supersonic combustion ramjet with upstream fuel injection  

NASA Astrophysics Data System (ADS)

This paper describes possible fuel injection scheme for airbreathing engines that use hydrocarbon fuels. The basic idea is to inject fuel at the spike tip of the supersonic inlet to achieve mixing and combustion efficiency with a limited length combustion chamber. A numerical code, able to solve the full Navier-Stokes equations in turbulent and reacting flows, is employed to obtain numerical simulations of the thermo-fluidynamic fields at different scramjet flight conditions, at Mach numbers of M=6.5 and 8. The feasibility of the idea of the upstream injection is checked for a simple axisymmetric configuration and relatively small size. The results are discussed in connection with the potential benefits deriving from the use of new ultra high temperature ceramics (UHTC).

Savino, Raffaele; Pezzella, Giuseppe

2003-09-01

351

Municipal solid waste combustion: Fuel testing and characterization  

SciTech Connect

The objective of this study is to screen and characterize potential biomass fuels from waste streams. This will be accomplished by determining the types of pollutants produced while burning selected municipal waste, i.e., commercial mixed waste paper residential (curbside) mixed waste paper, and refuse derived fuel. These materials will be fired alone and in combination with wood, equal parts by weight. The data from these experiments could be utilized to size pollution control equipment required to meet emission standards. This document provides detailed descriptions of the testing methods and evaluation procedures used in the combustion testing and characterization project. The fuel samples will be examined thoroughly from the raw form to the exhaust emissions produced during the combustion test of a densified sample.

Bushnell, D.J.; Canova, J.H.; Dadkhah-Nikoo, A.

1990-10-01

352

Explosively Driven Combustion of Shock-Dispersed Fuels  

NASA Astrophysics Data System (ADS)

The paper presents small-scale experiments with 1-g charges that explore the topic of post-detonation energy release due to the combustion of explosively dispersed fuels in the ambient air. To this end we have designed a new prototype small-scale charge, called Shock-Dispersed Fuel (SDF) charge. It consists of a lightweight, small paper cylinder filled with about one gram of a combustible powder (e.g., flake aluminum) surrounding a spherical PETN booster of 0.5 g. We have tested the SDF charges in a number of different environments, realized as closed steel vessels of simple geometry (barometric bombs). Three of the bombs vary in volume (6.6 1, 21.2 1 and 40.5 1), while their aspect ratio L/D is kept constant at about 1. Two further bombs are comparable to the smallest bomb in volume (6.3 1), but provide different aspect ratios: L/D = 4.6 and 12.5. In addition, we have also performed tests in a tunnel-model with an L/D = 37.5. Our basic goal is to assess the performance of the charges by means of the combustion-related pressure built-up. Thus we contrast experiments on SDF charges in air with tests in nitrogen, to inhibit combustion, and with tests on conventional charges. Experiments and theoretical estimates on the expected overpressure allow one to formulate various indicators of the combustion effectiveness. For SDF charges these indicate that the combustion effectiveness decreases with increasing volume of the barometric bomb, and also with increasing aspect ratio at constant volume. This bears importance to the performance of SDF charges in tunnel environments. The performance losses reflect - at least in part - geometry-specific constraints on the mixing between fuel and air.

Neuwald, P.

2006-07-01

353

Sonically Enhanced Combustion of Coal Water Slurry Fuel.  

NASA Astrophysics Data System (ADS)

An investigation was performed to demonstrate that a high intensity acoustic field can enhance the convective transfer processes occurring during CWSF (coal water slurry fuel) combustion. It was carried out in a 300,000 Btu/h sonic combustor. For the runs conducted, SPLs of 156 dB and 145 dB, respectively, were measured below the fuel injection point and before the exit to the combustor. Frequency was held at 1400 Hz. Combustion efficiency was improved when the extent of burnout was well below 100% and when the droplet size distribution was relatively coarse. The maximum improvement in burnout was 7.9%, under the coarsest atomization conditions investigated. Results from modelling show that sonically enhanced heat transfer plays a negligible role in improving the rate of combustion of CWSF. However, such enhancement may well be important for other applications (e.g. spray drying) involving longer drying times and/or small steady slip velocities. The application of a sonic field improves the rate of combustion of CWSF mainly through increased mass transfer rates, the enhancement being greatest for relatively coarse atomization. It is commonly accepted that the largest particles of fuel are the most likely to avoid full burnout in a practical combustor and thus contribute to erosion, slagging, and fouling via inertial mechanisms. By acting preferentially on these particles, operational difficulties can be minimized.

Ramachandran, Prakash

1990-01-01

354

FUEL FORMULATION EFFECTS ON DIESEL FUEL INJECTION, COMBUSTION, EMISSIONS AND EMISSION CONTROL  

Microsoft Academic Search

This paper describes work under a U.S. DOE sponsored Ultra Clean Fuels project entitled ''Ultra Clean Fuels from Natural Gas,'' Cooperative Agreement No. DE-FC26-01NT41098. In this study we have examined the incremental benefits of moving from low sulfur diesel fuel and ultra low sulfur diesel fuel to an ultra clean fuel, Fischer-Tropsch diesel fuel produced from natural gas. Blending with

A Boehman; M Alam; J Song; R Acharya; J Szybist; V Zello; K Miller

2003-01-01

355

Fuel injector nozzle for an internal combustion engine  

DOEpatents

A direct injection fuel injector includes a nozzle tip having a plurality of passages allowing fluid communication between an inner nozzle tip surface portion and an outer nozzle tip surface portion and directly into a combustion chamber of an internal combustion engine. A first group of the passages have inner surface apertures located substantially in a first common plane. A second group of the passages have inner surface apertures located substantially in at least a second common plane substantially parallel to the first common plane. The second group has more passages than the first group.

Cavanagh, Mark S. (Bloomington, IL); Urven, Jr., Roger L. (Colona, IL); Lawrence, Keith E. (Peoria, IL)

2008-11-04

356

Fuel cycle analysis for fossil energy systems: coal combustion  

SciTech Connect

Elements of the fuel cycle for coal combustion in power generation are examined; and information on economics, technological status, energy efficiencies, and environmental issues is reviewed. Overall background information is provided for guidance in identifying issues and establishing needs and priorities for engineering research, development, and demonstration. The elements treated include mining, transportation, coal preparation, direct combustion, and environmental control technology. The treatment used differs from that of usual compendiums in its emphasis on integrated examination and presentation directed primarily toward providing bases for general assessment and for guidance in program development. Emphasis is on program identification as opposed to advocacy.

Greenstreet, W.L.; Carmichael, R.L.

1981-02-01

357

Fuel injector nozzle for an internal combustion engine  

DOEpatents

A direct injection fuel injector includes a nozzle tip having a plurality of passages allowing fluid communication between an inner nozzle tip surface portion and an outer nozzle tip surface portion and directly into a combustion chamber of an internal combustion engine. A first group of the passages have inner surface apertures located substantially in a first common plane. A second group of the passages have inner surface apertures located substantially in at least a second common plane substantially parallel to the first common plane. The second group has more passages than the first group.

Cavanagh, Mark S. (Bloomington, IL); Urven, Jr., Roger L. (Colona, IL); Lawrence, Keith E. (Peoria, IL)

2011-03-22

358

Fuel injector nozzle for an internal combustion engine  

DOEpatents

A direct injection fuel injector includes a nozzle tip having a plurality of passages allowing fluid communication between an inner nozzle tip surface portion and an outer nozzle tip surface portion and directly into a combustion chamber of an internal combustion engine. A first group of the passages have inner surface apertures located substantially in a first common plane. A second group of the passages have inner surface apertures located substantially in at least a second common plane substantially parallel to the first common plane. The second group has more passages than the first group.

Cavanagh, Mark S. (Bloomington, IL); Urven, Jr., Roger L. (Colona, IL); Lawrence, Keith E. (Peoria, IL)

2007-11-06

359

Fuel Injector Nozzle For An Internal Combustion Engine  

DOEpatents

A direct injection fuel injector includes a nozzle tip having a plurality of passages allowing fluid communication between an inner nozzle tip surface portion and an outer nozzle tip surface portion and directly into a combustion chamber of an internal combustion engine. A first group of the passages have inner surface apertures located substantially in a first common plane. A second group of the passages have inner surface apertures located substantially in at least a second common plane substantially parallel to the first common plane. The second group has more passages than the first group.

Cavanagh, Mark S. (Bloomington, IL); Urven, Jr.; Roger L. (Colona, IL); Lawrence, Keith E. (Peoria, IL)

2006-04-25

360

Sectoral combustor for burning low-BTU fuel gas  

DOEpatents

A high-temperature combustor for burning low-BTU coal gas in a gas turbine is disclosed. The combustor includes several separately removable combustion chambers each having an annular sectoral cross section and a double-walled construction permitting separation of stresses due to pressure forces and stresses due to thermal effects. Arrangements are described for air-cooling each combustion chamber using countercurrent convective cooling flow between an outer shell wall and an inner liner wall and using film cooling flow through liner panel grooves and along the inner liner wall surface, and for admitting all coolant flow to the gas path within the inner liner wall. Also described are systems for supplying coal gas, combustion air, and dilution air to the combustion zone, and a liquid fuel nozzle for use during low-load operation. The disclosed combustor is fully air-cooled, requires no transition section to interface with a turbine nozzle, and is operable at firing temperatures of up to 3000.degree. F. or within approximately 300.degree. F. of the adiabatic stoichiometric limit of the coal gas used as fuel.

Vogt, Robert L. (Schenectady, NY)

1980-01-01

361

Pyrolysis, ignition and combustion of solid fuels for ramjet applications  

SciTech Connect

The utilization of the most attractive metal additive, boron powder, in ramjet application still remains in the development stages. On the other hand, the very popular metal additive, magnesium, has very good ignitability and high combustion efficiency, but has a low heating value. The scope of this study was concentrated on these two kinds of metal additive and three different types of polymeric binders - HTPB, PTFE, and high energy poly (BAMO/NMMO). Using various combinations of these ingredients, a total of 17 different solid fuels were investigated. The purpose of the present research was to study the pyrolysis, ignition, and combustion characteristics of the above mentioned fuel samples, using high-powered CO{sub 2} laser testing system, a windowed strand burning setup, and two cross-flow combustion facilities - a kerosene burner and a blowdown supersonic wind tunnel. A hypothesis based on absorptivity, thermal diffusivity, and reactivity was proposed to interpret the observed phenomena. The effects of four additives on ignition delay time of boron/HTPB fuels were measured, and CeF{sub 3} was found to be the most effective one. A sample composed of 20% Mg/30% B.50% PTFE exhibited a highly vigorous reaction, and it appears to be very promising for improving boron combustion efficiency. Mg/PTFE/Viton A fuel considered as a possible candidate for ramjet (solid ducted rocket) applications, exhibited a very unique burning phenomenon - ambient oxygen has an adverse effect on the ignition delay time and also on the burning rate. Based on the experimental results, it can be concluded that with the help of a highly energetic binder, an efficient combustion of boron can be expected.

Chen, D.M.

1988-01-01

362

Plasma Reforming And Partial Oxidation Of Hydrocarbon Fuel Vapor To Produce Synthesis Gas And/Or Hydrogen Gas  

DOEpatents

Methods and systems are disclosed for treating vapors from fuels such as gasoline or diesel fuel in an internal combustion engine, to form hydrogen gas or synthesis gas, which can then be burned in the engine to produce more power. Fuel vapor, or a mixture of fuel vapor and exhaust gas and/or air, is contacted with a plasma, to promote reforming reactions between the fuel vapor and exhaust gas to produce carbon monoxide and hydrogen gas, partial oxidation reactions between the fuel vapor and air to produce carbon monoxide and hydrogen gas, or direct hydrogen and carbon particle production from the fuel vapor. The plasma can be a thermal plasma or a non-thermal plasma. The plasma can be produced in a plasma generating device which can be preheated by contact with at least a portion of the hot exhaust gas stream, thereby decreasing the power requirements of the plasma generating device.

Kong, Peter C. (Idaho Falls, ID); Detering, Brent A. (Idaho Falls, ID)

2004-10-19

363

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

DOEpatents

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

Biruduganti, Munidhar S. (Naperville, IL); Gupta, Sreenath Borra (Naperville, IL); Sekar, R. Raj (Naperville, IL); McConnell, Steven S. (Shorewood, IL)

2008-11-25

364

Greenhouse impact due to the use of combustible fuels: Life cycle viewpoint and relative radiative forcing commitment  

SciTech Connect

Extensive information on the greenhouse impacts of various human actions is important in developing effective climate change mitigation strategies. The greenhouse impacts of combustible fuels consist not only of combustion emissions but also of emissions from the fuel production chain and possible effects on the ecosystem carbon storages. It is important to be able to assess the combined, total effect of these different emissions and to express the results in a comprehensive way. In this study, a new concept called relative radiative forcing commitment (RRFC) is presented and applied to depict the greenhouse impact of some combustible fuels currently used in Finland. RRFC is a ratio that accounts for the energy absorbed in the Earth system due to changes in greenhouse gas concentrations (production and combustion of fuel) compared to the energy released in the combustion of fuel. RRFC can also be expressed as a function of time in order to give a dynamic cumulative picture on the caused effect. Varying time horizons can be studied separately, as is the case when studying the effects of different climate policies on varying time scales. The RRFC for coal for 100 years is about 170, which means that in 100 years 170 times more energy is absorbed in the atmosphere due to the emissions of coal combustion activity than is released in combustion itself. RRFC values of the other studied fuel production chains varied from about 30 (forest residues fuel) to 190 (peat fuel) for the 100-year study period. The length of the studied time horizon had an impact on the RRFC values and, to some extent, on the relative positions of various fuels.

Kirkinen, J.; Palosuo, T.; Holmgren, K.; Savolainen, I. [VTT Technical Research Center Finland, Espoo (Finland)

2008-09-15

365

Multi-Dimensional Measurements of Combustion Species in Flame Tube and Sector Gas Turbine Combustors  

NASA Technical Reports Server (NTRS)

The higher temperature and pressure cycles of future aviation gas turbine combustors challenge designers to produce combustors that minimize their environmental impact while maintaining high operation efficiency. The development of low emissions combustors includes the reduction of unburned hydrocarbons, smoke, and particulates, as well as the reduction of oxides of nitrogen (NO(x)). In order to better understand and control the mechanisms that produce emissions, tools are needed to aid the development of combustor hardware. Current methods of measuring species within gas turbine combustors use extractive sampling of combustion gases to determine major species concentrations and to infer the bulk flame temperature. These methods cannot be used to measure unstable combustion products and have poor spatial and temporal resolution. The intrusive nature of gas sampling may also disturb the flow structure within a combustor. Planar laser-induced fluorescence (PLIF) is an optical technique for the measurement of combustion species. In addition to its non-intrusive nature, PLIF offers these advantages over gas sampling: high spatial resolution, high temporal resolution, the ability to measure unstable species, and the potential to measure combustion temperature. This thesis considers PLIF for in-situ visualization of combustion species as a tool for the design and evaluation of gas turbine combustor subcomponents. This work constitutes the first application of PLIF to the severe environment found in liquid-fueled, aviation gas turbine combustors. Technical and applied challenges are discussed. PLIF of OH was used to observe the flame structure within the post flame zone of a flame tube combustor, and within the flame zone of a sector combustor, for a variety of fuel injector configurations. OH was selected for measurement because it is a major combustion intermediate, playing a key role in the chemistry of combustion, and because its presence within the flame zone can serve as a qualitative marker of flame temperature. All images were taken in the environment of actual engines during flight, using actual jet fuel. The results of the PLIF study led directly to the modification of a fuel injector.

Hicks, Yolanda Royce

1996-01-01

366

Greenhouse gas emissions assessment of hydrogen and kerosene-fueled aircraft propulsion  

Microsoft Academic Search

The paper highlights the importance of hydrogen as a promising alternative for future aircraft fuel, with respect to reduced environmental impact, increased sustainability, high energy content and favorable combustion kinetics, since the rapid growth and dependence of aircraft propulsion on fossil fuels are unsustainable. This paper compares the environmental impact of hydrogen and kerosene-fueled aircraft, in terms of greenhouse gas

H. Nojoumi; I. Dincer; G. F. Naterer

2009-01-01

367

Fuel-Air Mixing Apparatus for Reducing Gas Turbine Combustor Exhaust Emissions.  

National Technical Information Service (NTIS)

A fuel-air mixer for use in a combustion chamber of a gas turbine engine is provided. The fuel air mixing apparatus comprises an annular fuel injector having a plurality of discrete plain jet orifices, a first swirler wherein the first swirler is located ...

F. J. Zupanc P. R. Yankowich

2004-01-01

368

Fossil Fuels: Natural Gas  

NSDL National Science Digital Library

This lesson provides an introduction to the use of natural gas as an energy source. Topics include its advantages (cleanliness, fewer carbon emissions), disadvantages (difficulty in transport and storage), sources, and usage. There is also a discussion of the creation and production of natural gas, the United States' production and reserves, and some potential new sources (coal bed methane, methane hydrates). The lesson includes an activity in which students investigate porosity and permeability in simulated sediments.

Pratte, John

369

Combustion research activities at the Gas Turbine Research Institute  

NASA Technical Reports Server (NTRS)

The Gas Turbine Research Institute (GTRI) is responsible mainly for basic research in aeronautical propulsion. An annular diffuser for the turbofan augmentor, combustor ignition performance, combustor airflow distribution, fuel injectors, a vaporizer fuel injector, and an airblast atomizer are discussed.

Shao, Zhongpu

1986-01-01

370

Electrostatic fuel conditioning of internal combustion engines  

NASA Technical Reports Server (NTRS)

Diesel engines were tested to determine if they are influenced by the presence of electrostatic and magnetic fields. Field forces were applied in a variety of configurations including pretreatment of the fuel and air, however, no affect on engine performance was observed.

Gold, P. I.

1982-01-01

371

Methods and systems to thermally protect fuel nozzles in combustion systems  

DOEpatents

A method of assembling a gas turbine engine is provided. The method includes coupling a combustor in flow communication with a compressor such that the combustor receives at least some of the air discharged by the compressor. A fuel nozzle assembly is coupled to the combustor and includes at least one fuel nozzle that includes a plurality of interior surfaces, wherein a thermal barrier coating is applied across at least one of the plurality of interior surfaces to facilitate shielding the interior surfaces from combustion gases.

Helmick, David Andrew; Johnson, Thomas Edward; York, William David; Lacy, Benjamin Paul

2013-12-17

372

Combustion chemistry and an evolving transportation fuel environment.  

SciTech Connect

The world currently faces tremendous energy challenges stemming from the need to curb potentially catastrophic anthropogenic climate change. In addition, many nations, including the United States, recognize increasing political and economic risks associated with dependence on uncertain and limited energy sources. For these and other reasons the chemical composition of transportation fuels is changing, both through introduction of nontraditional fossil sources, such as oil sands-derived fuels in the US stream, and through broader exploration of biofuels. At the same time the need for clean and efficient combustion is leading engine research towards advanced low-temperature combustion strategies that are increasingly sensitive to this changing fuel chemistry, particularly in the areas of pollutant formation and autoignition. I will highlight the new demands that advanced engine technologies and evolving fuel composition place on investigations of fundamental reaction chemistry. I will focus on recent progress in measuring product formation in elementary reactions by tunable synchrotron photoionization, on the elucidation of pressure-dependent effects in the reactions of alkyl and substituted alkyl radicals with O{sub 2}, and on new combined efforts in fundamental combustion chemistry and engine performance studies of novel potential biofuels.

Taatjes, Craig A. (Org. 8353, Combustion Chemistry Department)

2010-05-01

373

Period of Combustion and Heat Exchange in the Combustion of Gaseous Fuel.  

National Technical Information Service (NTIS)

This is a review of recent Soviet research and development on gas and oil fired burners for industrial boilers, heating systems, and gas turbine engines. Attention is focused on the ignition of gaseous fuel, chiefly natural gas. The chief points of intere...

A. S. Isserlin M. I. Pevzner

1969-01-01

374

System evaluation and LBTU fuel combustion studies for IGCC power generation  

SciTech Connect

The integration of gas turbines and combined cycle systems with advances in coal gasification and gas stream cleanup systems will result in economically viable IGCC systems. Optimization of IGCC systems for both emission levels and cost of electricity is critical to achieving this goal. A technical issue is the ability to use a wide range of coal and petroleum-based fuel gases in conventional gas turbine combustor hardware. In order to characterize the acceptability of these syngases for gas turbines, combustion studies were conducted with simulated coal gases using full-scale advanced gas turbine (7F) combustor components. It was found that NO{sub x} emissions could be correlated as a simple function of stoichiometric flame temperature for a wide range of heating values while CO emissions were shown to depend primarily on the H{sub 2} content of the fuel below heating values of 130 Btu/scf (5,125 kJ/NM{sup 3}) and for H{sub 2}/CO ratios less than unity. The test program further demonstrated the capability of advanced can-annular combustion systems to burn fuels from air-blown gasifiers with fuel lower heating values as low as 90 Btu/scf (3,548 kJ/NM{sup 3}) at 2,300 F (1,260 C) firing temperature. In support of ongoing economic studies, numerous IGCC system evaluations have been conducted incorporating a majority of the commercial or near-commercial coal gasification systems coupled with F series gas turbine combined cycles. Both oxygen and air-blown configurations have been studied, in some cases with high and low-temperature gas cleaning systems. It has been shown that system studies must start with the characteristics and limitations of the gas turbine if output and operating economics are to be optimized throughout the range of ambient operating temperature and load variation.

Cook, C.S.; Corman, J.C.; Todd, D.M. [GE Power Generation, Schenectady, NY (United States)

1995-10-01

375

Flame blowout and pollutant emissions in vitiated combustion of conventional and bio-derived fuels  

NASA Astrophysics Data System (ADS)

The widening gap between the demand and supply of fossil fuels has catalyzed the exploration of alternative sources of energy. Interest in the power, water extraction and refrigeration (PoWER) cycle, proposed by the University of Florida, as well as the desirability of using biofuels in distributed generation systems, has motivated the exploration of biofuel vitiated combustion. The PoWER cycle is a novel engine cycle concept that utilizes vitiation of the air stream with externally-cooled recirculated exhaust gases at an intermediate pressure in a semi-closed cycle (SCC) loop, lowering the overall temperature of combustion. It has several advantages including fuel flexibility, reduced air flow, lower flame temperature, compactness, high efficiency at full and part load, and low emissions. Since the core engine air stream is vitiated with the externally cooled exhaust gas recirculation (EGR) stream, there is an inherent reduction in the combustion stability for a PoWER engine. The effect of EGR flow and temperature on combustion blowout stability and emissions during vitiated biofuel combustion has been characterized. The vitiated combustion performance of biofuels methyl butanoate, dimethyl ether, and ethanol have been compared with n-heptane, and varying compositions of syngas with methane fuel. In addition, at high levels of EGR a sharp reduction in the flame luminosity has been observed in our experimental tests, indicating the onset of flameless combustion. This drop in luminosity may be a result of inhibition of processes leading to the formation of radiative soot particles. One of the objectives of this study is finding the effect of EGR on soot formation, with the ultimate objective of being able to predict the boundaries of flameless combustion. Detailed chemical kinetic simulations were performed using a constant-pressure continuously stirred tank reactor (CSTR) network model developed using the Cantera combustion code, implemented in C++. Results have been presented showing comparative trends in pollutant emissions generation, flame blowout stability, and combustion efficiency. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

Singh, Bhupinder

376

Internal combustion engine having exhaust gas recirculation system  

Microsoft Academic Search

An internal combustion engine has an exhaust gas recirculation system including a recirculation valve for controlling the amount of exhaust gas returned to the intake system. The position or opening of the valve is controlled to a desired position in accordance with a memory in a memory device storing desired valve positions under various combinations of the engine load and

K. Iida; K. Okazaki; Y. Yada

1983-01-01

377

Combustion and emissions characteristics of compression-ignition engine using dual ammonia-diesel fuel  

Microsoft Academic Search

This study investigated the combustion and emissions characteristics of a compression-ignition engine using a dual-fuel approach with ammonia and diesel fuel. Ammonia can be regarded as a hydrogen carrier and used as a fuel, and its combustion does not produce carbon dioxide. In this study, ammonia vapor was introduced into the intake manifold and diesel fuel was injected into the

Aaron J. Reiter; Song-Charng Kong

2011-01-01

378

Experimental Investigation of the Effects of Fuel Characteristics on High Efficiency Clean Combustion (HECC) in a Light-Duty Diesel Engine  

SciTech Connect

An experimental study was performed to understand fuel property effects on low temperature combustion (LTC) processes in a light-duty diesel engine. These types of combustion modes are often collectively referred to as high efficiency clean combustion (HECC). A statistically designed set of research fuels, the Fuels for Advanced Combustion Engines (FACE), were used for this study. Engine conditions consistent with low speed cruise (1500 rpm, 2.6 bar BMEP) were chosen for investigating fuel property effects on HECC operation in a GM 1.9-L common rail diesel engine. The FACE fuel matrix includes nine combinations of fuel properties including cetane number (30 to 55), aromatic contents (20 to 45 %), and 90 % distillation temperature (270 to 340 C). HECC operation was achieved with high levels of EGR and adjusting injection parameters, e.g. higher fuel rail pressure and single injection event, which is also known as Premixed Charge Compression Ignition (PCCI) combustion. Engine performance, pollutant emissions, and details of the combustion process are discussed in this paper. Cetane number was found to significantly affect the combustion process with variations in the start of injection (SOI) timing, which revealed that the ranges of SOI timing for HECC operation and the PM emission levels were distinctively different between high cetane number (55) and low cetane number fuels (30). Low cetane number fuels showed comparable levels of regulated gas emissions with high cetane number fuels and had an advantage in PM emissions.

Cho, Kukwon [ORNL; Han, Manbae [ORNL; Wagner, Robert M [ORNL; Sluder, Scott [ORNL

2009-01-01

379

Fuels Containing Methane of Natural Gas in Solution  

NASA Technical Reports Server (NTRS)

While exploring ways of producing better fuels for propulsion of a spacecraft on the Mars sample return mission, a researcher at Johnson Space Center (JSC) devised a way of blending fuel by combining methane or natural gas with a second fuel to produce a fuel that can be maintained in liquid form at ambient temperature and under moderate pressure. The use of such a blended fuel would be a departure for both spacecraft engines and terrestrial internal combustion engines. For spacecraft, it would enable reduction of weights on long flights. For the automotive industry on Earth, such a fuel could be easily distributed and could be a less expensive, more efficient, and cleaner-burning alternative to conventional fossil fuels. The concept of blending fuels is not new: for example, the production of gasoline includes the addition of liquid octane enhancers. For the future, it has been commonly suggested to substitute methane or compressed natural gas for octane-enhanced gasoline as a fuel for internal-combustion engines. Unfortunately, methane or natural gas must be stored either as a compressed gas (if kept at ambient temperature) or as a cryogenic liquid. The ranges of automobiles would be reduced from their present values because of limitations on the capacities for storage of these fuels. Moreover, technical challenges are posed by the need to develop equipment to handle these fuels and, especially, to fill tanks acceptably rapidly. The JSC alternative to provide a blended fuel that can be maintained in liquid form at moderate pressure at ambient temperature has not been previously tried. A blended automotive fuel according to this approach would be made by dissolving natural gas in gasoline. The autogenous pressure of this fuel would eliminate the need for a vehicle fuel pump, but a pressure and/or flow regulator would be needed to moderate the effects of temperature and to respond to changing engine power demands. Because the fuel would flash as it entered engine cylinders, relative to gasoline, it would disperse more readily and therefore would mix with air more nearly completely. As a consequence, this fuel would burn more nearly completely (and, hence, more cleanly) than gasoline does. The storage density of this fuel would be similar to that of gasoline, but its energy density would be such that the mileage (more precisely, the distance traveled per unit volume of fuel) would be greater than that of either gasoline or compressed natural gas. Because the pressure needed to maintain the fuel in liquid form would be more nearly constant and generally lower than that needed to maintain compressed natural gas in liquid form, the pressure rating of a tank used to hold this fuel could be lower than that of a tank used to hold compressed natural gas. A mixture of natural gas and gasoline could be distributed more easily than could some alternative fuels. A massive investment in new equipment would not be necessary: One could utilize the present fuel-distribution infrastructure and could blend the gasoline and natural gas at almost any place in the production or distribution process - perhaps even at the retail fuel pump. Yet another advantage afforded by use of a blend of gasoline and natural gas would be a reduction in the amount of gasoline consumed. Because natural gas costs less than gasoline does and is in abundant supply in the United States, the cost of automotive fuel and the demand for imported oil could be reduced.

Sullivan, Thomas A.

2004-01-01

380

Numerical simulation for explosion wave propagation of combustible mixture gas  

Microsoft Academic Search

A two-dimensional multi-material code was indigenously developed to investigate the effects of duct boundary conditions and\\u000a ignition positions on the propagation law of explosion wave for hydrogen and methane-based combustible mixture gas. In the\\u000a code, Young’s technique was employed to track the interface between the explosion products and air, and combustible function\\u000a model was adopted to simulate ignition process. The

Cheng Wang; Jian-guo Ning; Tian-bao Ma

2008-01-01

381

Control of mercury vapor emissions from combustion flue gas  

Microsoft Academic Search

Goal, Scope and Background  Mercury (Hg) emission from combustion flue gas is a significant environmental concern due to its toxicity and high volatility.\\u000a A number of the research efforts have been carried out in the past decade exploiting mercury emission, monitoring and control\\u000a from combustion flue gases. Most recently, increasing activities are focused on evaluating the behavior of mercury in coal

Rong Yan; David Tee Liang; Joo Hwa Tay

2003-01-01

382

Combustion Instability in an Acid-Heptane Rocket with a Pressurized-Gas Propellant Pumping System  

NASA Technical Reports Server (NTRS)

Results of experimental measurements of low-frequency combustion instability of a 300-pound thrust acid-heptane rocket engine were compared to the trends predicted by an analysis of combustion instability in a rocket engine with a pressurized-gas propellant pumping system. The simplified analysis, which assumes a monopropellant model, was based on the concept of a combustion the delay occurring from the moment of propellant injection to the moment of propellant combustion. This combustion time delay was experimentally measured; the experimental values were of approximately half the magnitude predicted by the analysis. The pressure-fluctuation frequency for a rocket engine with a characteristic length of 100 inches and operated at a combustion-chamber pressure of 280 pounds per square inch absolute was 38 cycles per second; the analysis indicated. a frequency of 37 cycles per second. Increasing combustion-chamber characteristic length decreased the pressure-fluctuation frequency, in conformity to the analysis. Increasing the chamber operating pressure or increasing the injector pressure drop increased the frequency. These latter two effects are contrary to the analysis; the discrepancies are attributed to the conflict between the assumptions made to simplify the analysis and the experimental conditions. Oxidant-fuel ratio had no apparent effect on the experimentally measured pressure-fluctuation frequency for acid-heptane ratios from 3.0 to 7.0. The frequencies decreased with increased amplitude of the combustion-chamber pressure variations. The analysis indicated that if the combustion time delay were sufficiently short, low-frequency combustion instability would be eliminated.

Tischler, Adelbert O.; Bellman, Donald R.

1951-01-01

383

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

384

Large-Eddy Simulations of Fuel-Air Mixing and Combustion in an Internal Combustion Engine  

NASA Astrophysics Data System (ADS)

Past studies of internal combustion (IC) engine steady-state flow field have employed the well-known KIVA code for steady-state predictions. However, it is also well known that this code is incapable of accurately capturing the impact of unsteady fuel-air mixing on the combustion process. Here, the latest KIVA-3V code has been modified to carry out large-eddy simulations (LES). In particular, the RANS k-e model has been replaced by a subgrid kinetic energy model and a fourth-order ENO scheme has been implemented to increase the accuracy of the discretization of the advection term. Finally, a subgrid model to simulate the small-scale turbulent mixing, combustion and heat release is implemented for reacting flows. Simulations using the new version of KIVA3V denoted here as KIVALES of temporal mixing layers and flows past rearward facing step demonstrate the improved accuracy of the LES model. Accuracy of the prediction is demonstrated by comparing with DNS, LES and experimental results obtained in the past. Finally, the new code is employed to simulate fuel-air mixing and combustion in a typical IC engine. Comparison with predictions using the conventional KIVA is used to demonstrate the ability of the new code.

Sone, Kazuo; Menon, Suresh

2000-11-01

385

Combustion of PMMA in a solid fuel ramjet  

SciTech Connect

The combustion behaviour of polymethyl methacrylate (PMMA) in a solid fuel ramjet was investigated using a connected pipe test facility. At pressures below 0,6 MPa almost no soot is formed, the flame is blueish and the regression rate appears to be primarily controlled by convection. At higher pressures, soot is formed and radiative heat transfer appears to be increasingly important. As a result, the regression rate becomes pressure dependant, while the effect of mass flux on regression rate decreases. Oxygen content in the air and air inlet temperature also affect combustion behaviour. No grain size effect on regression rate is noticed. Spectroscopic measurements demonstrated the presence of OH, C/sub 2/ and CH in the combustion chamber. The combustion efficiency varied between 70 and 76% and can be increased by increasing the size of the aft mixing chamber, the fuel grain length or the oxygen content in the air. Cold flow computer calculations were performed and showed good agreement with experimentally obtained results.

Korting, P.A.O.G.; Van der Geld, C.W.M.; Vos, J.B.; Wijchers, T.; Nina, M.N.R.

1986-01-01

386

Combustion  

NASA Astrophysics Data System (ADS)

The process whereby a substance is combined with oxygen with the production of heat. Burning is a familiar example of this process. The energy required to propel chemical rockets is provided by the combustion of fuel with an oxidant at very high temperatures. A common oxidant is liquid oxygen (often denoted by LOX). Others include hydrogen peroxide and nitrogen tetroxide....

Murdin, P.

2000-11-01

387

Exhaust gas recirculation system for an internal combustion engine  

DOEpatents

An exhaust gas recirculation system for an internal combustion engine comprises an exhaust driven turbocharger having a low pressure turbine outlet in fluid communication with an exhaust gas conduit. The turbocharger also includes a low pressure compressor intake and a high pressure compressor outlet in communication with an intake air conduit. An exhaust gas recirculation conduit fluidly communicates with the exhaust gas conduit to divert a portion of exhaust gas to a low pressure exhaust gas recirculation branch extending between the exhaust gas recirculation conduit and an engine intake system for delivery of exhaust gas thereto. A high pressure exhaust gas recirculation branch extends between the exhaust gas recirculation conduit and the compressor intake and delivers exhaust gas to the compressor for mixing with a compressed intake charge for delivery to the intake system.

Wu, Ko-Jen

2013-05-21

388

Application of active combustion instability control to a heavy duty gas turbine  

SciTech Connect

During the prototype shop tests, the Model V84.3A ring combustor gas turbine unexpectedly exhibited a noticeable humming caused by self-excited flame vibrations in the combustion chamber for certain operating conditions. The amplitudes of the pressure fluctuations in the combustor were unusually high when compared to the previous experience with silo combustor machines. As part of the optimization program, the humming was investigated and analyzed. To date, combustion instabilities in real, complex combustors cannot be predicted analytically during the design phase. Therefore, and as a preventive measure against future surprises by humming, a feedback system was developed which counteracts combustion instabilities by modulation of the fuel flow rate with rapid valves (active instability control, AIC). The AIC achieved a reduction of combustion-induced pressure amplitudes by 86%. The combustion instability in the Model V84.3A gas turbine was eliminated by changes of the combustor design. Therefore, the AIC is not required for the operation of customer gas turbines.

Seume, J.R.; Vortmeyer, N.; Krause, W. [Siemens Power Generation, Berlin (Germany); Hermann, J.; Hantschk, C.C.; Zangl, P.; Gleis, S.; Vortmeyer, D. [Technical Univ. of Munich (Germany). Lehrstruhl B. Fuer Thermodynamik; Orthmann, A. [pad Software, Haar-Salmdorf (Germany)

1998-10-01

389

Combustion Characteristics of Liquid Normal Alkane Fuels in a Model Combustor of Supersonic Combustion Ramjet Engine  

Microsoft Academic Search

Effect of kinds of one-component n-alkane liquid fuels on combustion characteristics was investigated experimentally using a model combustor of scramjet engine. The inlet condition of a model combustor is 2.0 of Mach number, up to 2400K of total temperature, and 0.38MPa of total pressure. Five kinds of n-alkane are tested, of which carbon numbers are 7, 8, 10, 13, and

2010-01-01

390

Combustion Dynamics and Control for Ultra Low Emissions in Aircraft Gas-Turbine Engines  

NASA Technical Reports Server (NTRS)

Future aircraft engines must provide ultra-low emissions and high efficiency at low cost while maintaining the reliability and operability of present day engines. The demands for increased performance and decreased emissions have resulted in advanced combustor designs that are critically dependent on efficient fuel/air mixing and lean operation. However, all combustors, but most notably lean-burning low-emissions combustors, are susceptible to combustion instabilities. These instabilities are typically caused by the interaction of the fluctuating heat release of the combustion process with naturally occurring acoustic resonances. These interactions can produce large pressure oscillations within the combustor and can reduce component life and potentially lead to premature mechanical failures. Active Combustion Control which consists of feedback-based control of the fuel-air mixing process can provide an approach to achieving acceptable combustor dynamic behavior while minimizing emissions, and thus can provide flexibility during the combustor design process. The NASA Glenn Active Combustion Control Technology activity aims to demonstrate active control in a realistic environment relevant to aircraft engines by providing experiments tied to aircraft gas turbine combustors. The intent is to allow the technology maturity of active combustion control to advance to eventual demonstration in an engine environment. Work at NASA Glenn has shown that active combustion control, utilizing advanced algorithms working through high frequency fuel actuation, can effectively suppress instabilities in a combustor which emulates the instabilities found in an aircraft gas turbine engine. Current efforts are aimed at extending these active control technologies to advanced ultra-low-emissions combustors such as those employing multi-point lean direct injection.

DeLaat, John C.

2011-01-01

391

Technology Assessment and Draft R and D Program Plan for Combustion of Nonconventional Fuels.  

National Technical Information Service (NTIS)

The development of combustion processes fueled either directly or indirectly with industrial, urban, and agricultural wastes (herein referred to as non-conventional fuels) is an effective strategy for the conservation of conventional fossil based fuels an...

1977-01-01

392

DEVELOPMENT OF SAMPLING AND ANALYTICAL METHODS FOR THE MEASUREMENT OF NITROUS OXIDE FROM FOSSIL FUEL COMBUSTION SOURCES  

EPA Science Inventory

The report documents the technical approach and results achieved while developing a grab sampling method and an automated, on-line gas chromatography method suitable to characterize nitrous oxide (N2O) emissions from fossil fuel combustion sources. he two methods developed have b...

393

DEVELOPMENT OF SAMPLING AND ANALYTICAL METHODS FOR THE MEASUREMENT OF NITROUS OXIDE FROM FOSSIL FUEL COMBUSTION SOURCES  

EPA Science Inventory

The report documents the technical approach and results achieved while developing a grab sampling method and an automated, on-line gas chromatography method suitable to characterize nitrous oxide (N2O) emissions from fossil fuel combustion sources. The two methods developed have...

394

Combustion characterization of beneficiated coal-based fuels  

SciTech Connect

The objectives of this project include: (1) the development of an engineering data base which will provide detailed information on the properties of BCFs influencing combustion, ash deposition, ash erosion, particulate collection, and emissions; and (2) the application of this technical data base to predict the performance and economic impacts of firing the BCFs in various commercial boiler designs. The technical approach used to develop the technical data includes: bench-scale fuel property, conbustion, and ash deposition tests; pilot-scale combustion and ash effects tests; and full-scale combustion tests. Subcontractors to CE to perform parts of the test work are the Massachusetts Institute of Technology (MIT), Physical Sciences, Inc. Technology Company (PSIT) and the University of North Dakota Energy and Environmental Research Center (UNDEERC). Twenty fuels will be characterized during the three-year base program: three feed coals, fifteen BCFs, and two conventionally cleaned coals for the full-scale tests. Approximately nine BCFs will be in dry ultra-fine coal (DUC) form, and six BCFs will be in coal-water fuel (CWF) form. Additional BCFs would be characterized during optional project supplements.

Chow, O.K.; Nsakala, N.Y.

1990-08-01

395

Characteristics of direct injection combustion fuelled by natural gas–hydrogen mixtures using a constant volume vessel  

Microsoft Academic Search

The effects of hydrogen addition and turbulence intensity on the natural gas–air turbulent combustion were studied experimentally using a constant volume vessel. Turbulence was generated by injecting the high-pressure fuel into the vessel. Flame propagation images and combustion characteristics via pressure-derived parameters were analyzed at various hydrogen volumetric fractions (from 0% to 40%) and the overall equivalence ratios of 0.6,

Jinhua Wang; Zuohua Huang; Haiyan Miao; Xibin Wang; Deming Jiang

2008-01-01

396

Combustion of Illinois coals and chars with natural gas. Technical report, December 1, 1991--February 29, 1992  

SciTech Connect

The combined combustion of coal and natural gas offers advantageous compared to burning coal or natural gas alone. For example, low volatile coals or low volatile chars derived from treatment or gasification processes can be of limited use due to their poor flammability characteristics. However, the use of natural gas in conjunction with the solid fuel can provide the necessary ``volatiles`` to enhance the combustion. Additionally, natural gas provides a clean cofiring fuel source which can enhance the usefulness of coals with high sulfur content. Addition of natural gas may reduce SO{sub x} emissions through increased sulfur retention in the ash and reduce NO{sub x} emissions by varying local stoichiometry and temperature levels. In this research program, studies of combined Illinois coal and natural gas combustion provide particle ignition, burnout rates and ash characterization, helping clarify the effect of coal and natural gas and identify the controlling parameters and mechanisms. The Drop Tube Furnace Facility allows detailed measurements of coal particle combustion under well-controlled conditions. The combustion characteristics of single coal particles are determined through a novel set of diagnostic techniques including in situ simultaneous measurements of particle morphology, temperature and velocity. The emphasis of the effort in the second quarter of this project was on the understanding of the ignition enhancement, burning rate processes during cofiring, and sulfur retention in the ash.

Buckinus, R.O.; Peters, J.E.; Krier, H.

1992-08-01

397

Gas Sensor Evaluations in Polymer Combustion Product Atmospheres  

NASA Technical Reports Server (NTRS)

Toxic gases produced by the combustion or thermo-oxidative degradation of materials such as wire insulation, foam, plastics, or electronic circuit boards in space shuttle or space station crew cabins may pose a significant hazard to the flight crew. Toxic gas sensors are routinely evaluated in pure gas standard mixtures, but the possible interferences from polymer combustion products are not routinely evaluated. The NASA White Sands Test Facility (WSTF) has developed a test system that provides atmospheres containing predetermined quantities of target gases combined with the coincidental combustion products of common spacecraft materials. The target gases are quantitated in real time by infrared (IR) spectroscopy and verified by grab samples. The sensor responses are recorded in real time and are compared to the IR and validation analyses. Target gases such as carbon monoxide, hydrogen cyanide, hydrogen chloride, and hydrogen fluoride can be generated by the combustion of poly(vinyl chloride), polyimide-fluoropolymer wire insulation, polyurethane foam, or electronic circuit board materials. The kinetics and product identifications for the combustion of the various materials were determined by thermogravimetric-IR spectroscopic studies. These data were then scaled to provide the required levels of target gases in the sensor evaluation system. Multisensor toxic gas monitors from two manufacturers were evaluated using this system. In general, the sensor responses satisfactorily tracked the real-time concentrations of toxic gases in a dynamic mixture. Interferences from a number of organic combustion products including acetaldehyde and bisphenol-A were minimal. Hydrogen bromide in the products of circuit board combustion registered as hydrogen chloride. The use of actual polymer combustion atmospheres for the evaluation of sensors can provide additional confidence in the reliability of the sensor response.

Delgado, Rafael H.; Davis, Dennis D.; Beeson, Harold D.

1999-01-01

398

Combustion of Illinois coals and chars with natural gas. Final technical report, September 1, 1991--August 31, 1992  

SciTech Connect

Combined combustion of coal and natural gas offers advantages compared to burning coal or natural gas alone. For example, low volatile coals (or chars) derived from treatment or gasification processes can be of limited use due to their poor flammability characteristics. However, the use of natural gas in conjunction with the solid fuel can provide the necessary ``volatiles`` to enhance the combustion. Also, natural gas provides a clean cofiring fuel source which can enhance the usefulness of coals with high sulfur content. Addition of natural gas may reduce SO{sub x} emissions through increased sulfur retention in the ash and reduce NO{sub x} emissions by varying local stoichiometry and temperature levels. This research program addresses the contributions and the mechanisms of cofiring natural gas with Illinois coal through studies of particle ignition, burning rates and ash characterization.

Buckius, R.O.; Peters, J.E.; Krier, H. [Illinois Univ., Urbana-Champaign, IL (United States)

1992-12-31

399

Wood-Fuel Use in Papua New Guinea: An Assessment of Industrial Combustion Equipment.  

National Technical Information Service (NTIS)

This report presents the results of an engineering and economic assessment of new and retrofit industrial combustion equipment for wood-fuel use in Papua New Guinea. Existing industrial combustion equipment and practices in Papua New Guinea are appraised....

M. S. Mendis

1980-01-01

400

Experimental investigation on the combustion and exhaust emission characteristics of biogas–biodiesel dual-fuel combustion in a CI engine  

Microsoft Academic Search

An experimental investigation was performed to study the influence of dual-fuel combustion characteristics on the exhaust emissions and combustion performance in a diesel engine fueled with biogas–biodiesel dual-fuel. In this work, the combustion pressure and the rate of heat release were evaluated under various conditions in order to analyze the combustion and emission characteristics for single-fuel (diesel and biodiesel) and

Seung Hyun Yoon; Chang Sik Lee

2011-01-01

401

Safety considerations in testing a fuel-rich aeropropulsion gas generator  

NASA Technical Reports Server (NTRS)

A catalyst containing reactor is being tested using a fuel-rich mixture of Jet A fuel and hot input air. The reactor product is a gaseous fuel that can be utilized in aeropropulsion gas turbine engines. Because the catalyst material is susceptible to damage from high temperature conditions, fuel-rich operating conditions are attained by introducing the fuel first into an inert gas stream in the reactor and then displacing the inert gas with reaction air. Once a desired fuel-to-air ratio is attained, only limited time is allowed for a catalyst induced reaction to occur; otherwise the inert gas is substituted for the air and the fuel flow is terminated. Because there presently is not a gas turbine combustor in which to burn the reactor product gas, the gas is combusted at the outlet of the test facility flare stack. This technique in operations has worked successfully in over 200 tests.

Rollbuhler, R. James; Hulligan, David D.

1991-01-01

402

Combustion Properties of Gas-Generating Pyrotechnics  

Microsoft Academic Search

This work focuses particularly on solid energetic materials designed to produce high-pressure gas for pressurizing or inflating devices. In coot gas generators sodium azide is often used. Unfortunately, this chemical exhibits drawbacks concerning toxicity and yield of gas. Another gas-generating agent is double base propellant, which has traditionally been used in the rocket-industry. However, it delivers toxic and reactive gases

K. ENGELEN; M. H. LEFEBVRE; J. DE RUYCK

2001-01-01

403

Oxy-fuel combustion boiler for CO 2 capturing: 50 kW-class model test and numerical simulation  

Microsoft Academic Search

A novel oxy-fuel burner was devised and integrated into a 50 kW-class furnace-type boiler system. A series of experiments\\u000a was conducted to verify its feasibility for industrial applications. Additionally, numerical simulations were performed and\\u000a the results validated against experimental data on the detailed physics inside the conventional-design combustion chamber.\\u000a The oxy-fuel burner, with the help of gas radiation, could effectively

Joon Ahn; Hyouck Ju Kim; Kyu Sung Choi

2010-01-01

404

Gas turbine combustion: Prospects and challenges  

Microsoft Academic Search

Gas turbines, first postulated and conceptually analyzed during the first decade of the twentieth century, became engineering reality in the late 1930s. During the last 50 years, aircraft gas turbine technology has developed gradually and continuously. The two families of gas turbines, aircraft and stationary, share a certain similarity, although their design requirements are significantly different. Both cases, however, incorporate

A. K. Gupta

1997-01-01

405

Fuels for Advanced Combustion Engines Research Diesel Fuels: Analysis of Physical and Chemical Properties  

SciTech Connect

The CRC Fuels for Advanced Combustion Engines working group has worked to identify a matrix of research diesel fuels for use in advanced combustion research applications. Nine fuels were specified and formulated to investigate the effects of cetane number aromatic content and 90% distillation fraction. Standard ASTM analyses were performed on the fuels as well as GC/MS and /u1H//u1/u3C NMR analyses and thermodynamic characterizations. Details of the actual results of the fuel formulations compared with the design values are presented, as well as results from standard analyses, such as heating value, viscosity and density. Cetane number characterizations were accomplished by using both the engine method and the Ignition Quality Tester (IQT/sT) apparatus.

Gallant, Tom [Pacific Northwest National Laboratory (PNNL); Franz, Jim [Pacific Northwest National Laboratory (PNNL); Alnajjar, Mikhail [Pacific Northwest National Laboratory (PNNL); Storey, John Morse [ORNL; Lewis Sr, Samuel Arthur [ORNL; Sluder, Scott [ORNL; Cannella, William C [Chevron, USA; Fairbridge, Craig [National Centre for Upgrading Technology, Canada; Hager, Darcy [National Centre for Upgrading Technology, Canada; Dettman, Heather [CANMET Energy; Luecke, Jon [National Renewable Energy Laboratory (NREL); Ratcliff, Matthew A. [National Renewable Energy Laboratory (NREL); Zigler, Brad [National Renewable Energy Laboratory (NREL)

2009-01-01

406

Investigation of combustion instability mechanisms in premixed gas turbines  

NASA Astrophysics Data System (ADS)

This thesis describes an investigation of self excited, combustion driven oscillations in low NOx gas turbines (LNGT). The first part of the thesis shows that LNGT instabilities are excited by a feedback mechanism between heat release, pressure, and equivalence ratio oscillations. It describes an analytical model that captures the important features of this mechanism and shows that the phase between the combustor pressure and velocity at the fuel injector, the time required for the reactive mixture to convect from the fuel injection point to the flame, and the acoustic period play key roles in the stability characteristics of LNGT combustors. Finally, it presents the results of experiments that closely agree with the key predictions of the model. The second part of this thesis characterizes the limit cycle oscillations in an unstable LNGT combustor. The processes that are responsible for limit cycle oscillations are discussed and it is shown that the limit cycle amplitude saturates when the mean and fluctuating velocities have similar magnitudes. This section also addresses the cyclic variability in measured pressure oscillations and shows that they are primarily random in nature. The third part of this thesis describes theoretical investigations of the interactions between a premixed flame and acoustic waves. It is shown that the multidimensionality of the acoustic field, the response of the flame to flow perturbations, and the production of vorticity all play important roles in these interactions. It is concluded that the linear processes controlling the stability characteristics of LNGT combustors are understood. It is suggested, however, that additional work is needed to characterize the nonlinear processes controlling the dynamics of the unstable system.

Lieuwen, Timothy Charles

407

Pressure measurements at the combustion front of gas-free pyrotechnic mixtures with low gas permeability  

Microsoft Academic Search

It is shown that the method of continuous measurement of pressure at the combustion front using an axial-force gauge is applicable\\u000a to gas-free pyrotechnic systems producing solid reaction products and characterized by low gas permeability of specimens in\\u000a the initial state. Small inclusions of a high-energy material producing gas combustion products are placed in the specimens\\u000a to check the reliability

V. F. Proskudin; V. A. Golubev; P. G. Berezhko

1997-01-01

408

Broad Specification Fuels Combustion Technology Program, Phase 2  

NASA Technical Reports Server (NTRS)

An experimental evaluation of two advanced technology combustor concepts was conducted to evolve and assess their capability for operation on broadened properties fuels. The concepts were based on the results of Phase 1 of the Broad Specification Fuel Combustor Technology Program which indicated that combustors with variable geometry or staged combustion zones had a flexibility of operation that could facilitate operation on these fuels. Emphasis in defining these concepts included the use of single pipe as opposed to duplex or staged fuels systems to avoid the risk of coking associated with the reduction in thermal stability expected in broadened properties fuels. The first concept was a variable geometry combustor in which the airflow into the primary zone could be altered through valves on the front while the second was an outgrowth of the staged Vorbix combustor, evolved under the NASA/P&W ECCP and EEE programs incorporating simplified fuel and air introduction. The results of the investigation, which involved the use of Experimental Referee Broad Specification (ERBS) fuel, indicated that in the form initially conceived, both of these combustor concepts were deficient in performance relative to many of the program goals for performance emissions. However, variations of both combustors were evaluated that incorporated features to simulate conceptual enhancement to demonstrate the long range potential of the combustor. In both cases, significant improvements relative to the program goals were observed.

Lohmann, R. P.; Jeroszko, R. A.; Kennedy, J. B.

1990-01-01

409

Multistage combustion method for inhibiting formation of nitrogen oxides  

Microsoft Academic Search

A method is disclosed, comprising injecting a primary fuel and air into a furnace to burn the fuel and form a first-stage combustion zone, the fuel being diluted with surrounding combustion gas and the air being supplied at a rate in excess of the stoichiometric rate required for the combustion of the fuel, and injecting a secondary fuel into the

N. Okigami; H. Hayasaka; Y. Sekiguchi; H. Tamuya

1983-01-01

410

Hot gas ignition temperatures of hydrocarbon fuel vapor-air mixtures  

Microsoft Academic Search

Laminar hot air jets of ¹\\/â to ³\\/â-inch diameter were employed to determine the hot gas ignition temperatures of various combustible vapor-air mixtures. The combustibles were n-hexane, n-octane, n-decane, a hydrocarbon jet fuel (JP-6) and an adipate ester aircraft engine oil (MIL-L-7808). Minimum ignition temperatures occurred at a fuel-air weight ratio of about 0.5 and were not greatly sensitive to

R. J. Cato; J. M. Kuchta

1965-01-01

411

Combustion-acoustic stability analysis for premixed gas turbine combustors  

NASA Technical Reports Server (NTRS)

Lean, prevaporized, premixed combustors are susceptible to combustion-acoustic instabilities. A model was developed to predict eigenvalues of axial modes for combustion-acoustic interactions in a premixed combustor. This work extends previous work by including variable area and detailed chemical kinetics mechanisms, using the code LSENS. Thus the acoustic equations could be integrated through the flame zone. Linear perturbations were made of the continuity, momentum, energy, chemical species, and state equations. The qualitative accuracy of our approach was checked by examining its predictions for various unsteady heat release rate models. Perturbations in fuel flow rate are currently being added to the model.

Darling, Douglas; Radhakrishnan, Krishnan; Oyediran, Ayo; Cowan, Lizabeth

1995-01-01

412

Some principles of combustion of homogeneous fuel-air mixtures in the cylinder of an internal combustion engine  

Microsoft Academic Search

An algorithm is presented for the problem of flame propagation rate in combustion of a homogeneous fuel-air mixture in the cylinder of an internal combustion engine. It is assumed that the mixture is not ``overturbulized'' and that the flame front is spherical. The model used for the phenomenon is based on a turbulent transport mechanism. In the near-wall region the

R. M. Petrichenko; A. B. Kanishchev; L. A. Zakharov; Bassam Kandakzhi

1990-01-01

413

Fuel property effects on engine combustion processes. Final report  

SciTech Connect

A major obstacle to improving spark ignition engine efficiency is the limitations on compression ratio imposed by tendency of hydrocarbon fuels to knock (autoignite). A research program investigated the knock problem in spark ignition engines. Objective was to understand low and intermediate temperature chemistry of combustion processes relevant to autoignition and knock and to determine fuel property effects. Experiments were conducted in an optically and physically accessible research engine, static reactor, and an atmospheric pressure flow reactor (APFR). Chemical kinetic models were developed for prediction of species evolution and autoignition behavior. The work provided insight into low and intermediate temperature chemistry prior to autoignition of n-butane, iso-butane, n-pentane, 1-pentene, n-heptane, iso-octane and some binary blends. Study of effects of ethers (MTBE, ETBE, TAME and DIPE ) and alcohols (methanol and ethanol) on the oxidation and autoignition of primary reference fuel (PRF) blends.

Cernansky, N.P.; Miller, D.L.

1995-04-27

414

Palladium-catalyzed combustion of methane: Simulated gas turbine combustion at atmospheric pressure  

SciTech Connect

Atmospheric pressure tests were performed in which a palladium catalyst ignites and stabilizes the homogeneous combustion of methane. Palladium exhibited a reversible deactivation at temperatures above 750 C, which acted to ``self-regulate`` its operating temperature. A properly treated palladium catalyst could be employed to preheat a methane/air mixture to temperatures required for ignition of gaseous combustion (ca. 800 C) without itself being exposed to the mixture adiabatic flame temperature. The operating temperature of the palladium was found to be relatively insensitive to the methane fuel concentration or catalyst inlet temperature over a wide range of conditions. Thus, palladium is well suited for application in the ignition and stabilization of methane combustion.

Griffin, T.; Weisenstein, W. [ABB Corporate Research Center, Daettwill (Switzerland)] [ABB Corporate Research Center, Daettwill (Switzerland); Scherer, V. [ABB Kraftwerke, Mannheim (Germany)] [ABB Kraftwerke, Mannheim (Germany); Fowles, M. [ICI Katalco, Cleveland (United Kingdom)] [ICI Katalco, Cleveland (United Kingdom)

1995-04-01

415

Investigation of combustion instability mechanisms in premixed gas turbines  

Microsoft Academic Search

This thesis describes an investigation of self excited, combustion driven oscillations in low NOx gas turbines (LNGT). The first part of the thesis shows that LNGT instabilities are excited by a feedback mechanism between heat release, pressure, and equivalence ratio oscillations. It describes an analytical model that captures the important features of this mechanism and shows that the phase between

Timothy Charles Lieuwen

1999-01-01

416

Compatibility of alternative fuels with advanced automotive gas turbine and stirling engines. A literature survey  

NASA Technical Reports Server (NTRS)

The application of alternative fuels in advanced automotive gas turbine and Stirling engines is discussed on the basis of a literature survey. These alternative engines are briefly described, and the aspects that will influence fuel selection are identified. Fuel properties and combustion properties are discussed, with consideration given to advanced materials and components. Alternative fuels from petroleum, coal, oil shale, alcohol, and hydrogen are discussed, and some background is given about the origin and production of these fuels. Fuel requirements for automotive gas turbine and Stirling engines are developed, and the need for certain reseach efforts is discussed. Future research efforts planned at Lewis are described.

Cairelli, J.; Horvath, D.

1981-01-01

417

Combustion and emissions of steady and intermittent high injection pressure sprays in a gas turbine combustor  

NASA Astrophysics Data System (ADS)

An experimental investigation has been carried out to study combustion characteristics and emissions of steady and intermittent high injection pressure sprays in a gas turbine combustor. A typical diesel injection system with a pintle type diesel injector is used to supply an intermittent spray through a typical gas turbine combustor. An accumulator pressurized reservoir has been installed in the injection system to supply a steady injected spray. Measurements of temperature distributions and species concentrations has been carried out for different injection pressures ranging from 1 MPa to 20 MPa for both intermittent and steady injected spray flames. Obtained results show that the injection pressure of liquid fuel sprays has an important role on spray combustion characteristics and emissions formations processes in the gas turbine combustors. Increasing the injection pressure, the Sauter mean diameter of spray droplets is decreased and the combustion process is considerably accelerated. A remarkable decrease occurs in nitric oxide concentrations in combustion products in the case of intermittent injected spray compared with the case of steady injected sprays.

El-Emam, S. H.

418

Reducing mode circulating fluid bed combustion  

DOEpatents

A method for combustion of sulfur-containing fuel in a circulating fluid bed combustion system wherein the fuel is burned in a primary combustion zone under reducing conditions and sulfur captured as alkaline sulfide. The reducing gas formed is oxidized to combustion gas which is then separated from solids containing alkaline sulfide. The separated solids are then oxidized and recycled to the primary combustion zone.

Lin, Yung-Yi (Katy, TX) [Katy, TX; Sadhukhan, Pasupati (Katy, TX) [Katy, TX; Fraley, Lowell D. (Sugarland, TX) [Sugarland, TX; Hsiao, Keh-Hsien (Houston, TX) [Houston, TX

1986-01-01

419

Combustion characteristics of hydrogen. Carbon monoxide based gaseous fuels  

NASA Technical Reports Server (NTRS)

An experimental rig program was conducted with the objective of evaluating the combuston performance of a family of fuel gases based on a mixture of hydrogen and carbon monoxide. These gases, in addition to being members of a family, were also representative of those secondary fuels that could be produced from coal by various gasification schemes. In particular, simulated Winkler, Lurgi, and Blue-water low and medium energy content gases were used as fuels in the experimental combustor rig. The combustor used was originally designed as a low NOx rich-lean system for burning liquid fuels with high bound nitrogen levels. When used with the above gaseous fuels this combustor was operated in a lean-lean mode with ultra long residence times. The Blue-water gas was also operated in a rich-lean mode. The results of these tests indicate the possibility of the existence of an 'optimum' gas turbine hydrogen - carbon monoxide based secondary fuel. Such a fuel would exhibit NOx and high efficiency over the entire engine operating range. It would also have sufficient stability range to allow normal light-off and engine acceleration. Solar Turbines Incorporated would like to emphasize that the results presented here have been obtained with experimental rig combustors. The technologies generated could, however, be utilized in future commercial gas turbines.

Notardonato, J. J.; White, D. J.; Kubasco, A. J.; Lecren, R. T.

1981-01-01

420

Combustion characterization of coal-water slurry fuel  

SciTech Connect

As a result of coal cleaning operations, a substantial amount of coal is disposed as waste into the ponds, effecting and endangering the environment. This study includes a technique to recover and utilize the waste coal fines from the preparation plant effluent streams and tailing ponds. Due to the large moisture content of the recovered coal fines, this investigation is focused on the utilization of coal fines in the coal-water slurry fuel. It is our belief that a blend of plant coal and waste coal fines can be used to produce a coal-water slurry fuel with the desired combustion characteristics required by the industry. The coal blend is composed of 85% clean coal and 15% recovered coal fines. The coal-water slurry is prepared at 60% solids with a viscosity less than 500 centipose and 80-90% of solid particles passing through 200 mesh. This paper contains analysis of clean coal, recovered coal fines, and coal-water slurry fuel as well as combustion characteristics.

Masudi, Houshang; Samudrala, S.

1996-12-31

421

Feasibility demonstration of the Thermal Ignition Combustion System (TICS) for high-pressure natural-gas-injected engine  

SciTech Connect

The objective of the program was the feasibility demonstration of the Thermal Ignition Combustion System (TICS) concept for the ignition and combustion of high-pressure injected natural gas. The TICS concept relies on the ignition of fuel by high-temperature combustion chamber walls without external ignition sources like spark plug, glow plug, or pilot diesel fuel. The program was successful in achieving ignition and combustion of natural gas in a single cylinder diesel engine with the TICS concept. An electronically controlled gas injector, designed and fabricated in the program, was used to inject natural gas at 13.8 to 20.7 MPa (2000 to 3000 psig) pressure in the TICS chamber. Cold starting of the test engine was achieved by external heating of the chamber for a few minutes. Natural gas ignition and combustion was then sustained by the high-temperature TICS chamber. The test engine was operated from idle to full load and from 600 to 1400 rpm engine-speed range.

Kalwani, R.M.; McNulty, D.; Badgley, P.; Kamo, R.

1989-02-01