Begell House Inc.
International Journal of Energy for a Clean Environment
IJECE
2150-3621
5
4
2004
A STUDY OF THE HETEROGENEOUS REDUCTION OF NO ON BITUMINOUS COAL CHARS
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A.
Arenillas
Instituto Nacional del Carbón (CSIC), Apartado 73, 33080 Oviedo, Spain
F.
Rubiera
Instituto Nacional del Carbón (CSIC), Apartado 73, 33080 Oviedo, Spain
J. B.
Parra
Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo, Spain
J. J.
Pis
Instituto Nacional del Carbón (CSIC), Apartado 73, 33080 Oviedo, Spain
The influence of char textural properties and coal rank on NO reduction was studied. A range of bituminous coals were pyrolyzed to obtain chars with different textural properties. A TG-MS was used to study the combustion behavior of the samples and the nitrogen compounds evolved. Experiments on the heterogeneous reduction of NO were carried out using chars with a different surface chemistry. The results show that NO-char interaction depends, to a large degree, on temperature. In the range of low temperatures (<750°C) surface complexes played an important role in the overall NO reduction. In the high-temperature range (>750°C), a different mechanism seems to be involved.
EXPERIMENTAL INVESTIGATION OF OXYGEN-ENRICHED LIFTED AND ATTACHED TURBULENT DIFFUSION FLAMES
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L. M.
Howard
Energy and Resources Research Institute, University of Leeds, Leeds LS2 9JT, UK
P. M.
Patterson
Energy and Resources Research Institute, University of Leeds, Leeds LS2 9JT, UK
L.
Yap
FlameTec, North Fort Myers, Florida 33903, USA
A.
Williams
Department of Fuel and Energy, Energy and Resources Research Institute / Centre for Computational Fluid Dynamics, University of Leeds, Leeds LS2 9JT, UK
M.
Pourkashanian
Energy-2050, Faculty of Engineering, University of Sheffield, Sheffield, S10 2TN, UK
C. W.
Wilson
Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD, UK
The interactions between turbulent fluid flow and chemical kinetics are examined experimentally in attached and lifted turbulent oxygen-enriched gaseous non-premixed flames by firing a methane jet vertically into a co-flowing oxidant shroud. Stable species, including nitrogen oxides, were measured using physical-probing techniques. Hydroxyl radical concentrations were monitored using laser-induced fluorescence (LIF). The level of oxygen enrichment in the shroud air was varied from 21% to 28% while maintaining constant average fuel-nozzle velocity and Reynolds number. Within the operating range, attached as well as lifted flames were observed. Physical and chemical differences in structure between attached and lifted flames are presented. With an increasing degree of oxygen, enrichment flames become shorter and more luminous in appearance. Attached flames appear more luminous with longer flame lengths. Significant amounts of oxygen were found on the fuel-rich side of the stoichiometric envelope in lifted flames, underscoring partially premixed characteristics near downstream locations.
FLAMELESS OXIDATION AND CONTINUED STAGED AIR COMBUSTION SYSTEMS FOR GAS TURBINES
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A.
Al-Halbouni
Gaswarme-Institut e. V. Essen, Germany
A.
Giese
Gaswarme-Institut e. V., Industrial Gas Utilization, 45356 Essen, Germany
Michael
Flamme
Schirnbecker Teiche 34, D-45279 Essen, Germany
M.
Brune
Gaswarme-Institut e. V., Industrial Gas Utilization, 45356 Essen, Germany
Currently investigations are running on the newly combustion systems of flameless oxidation and continued staged air that are expected to be economically and ecologically more efficient than the premixed combustion systems used in gas turbine combustion chambers. Both mentioned combustion systems ensure through high internal flue-gas recirculation rates and continuously staged air, respectively, extremely low NOx emission. Basis investigations on both combustion concepts using natural gas at atmospheric pressure had been done. Results achieved proved that both burner systems lead to single-digit NOx and CO emission values. In this contribution, achieved results will be presented.
STATUS OF CO-COMBUSTION OF COAL AND BIOMASS IN EUROPE
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Hartmut
Spliethoff
Section Thermal Power Engineering, Faculty of Design, Construction and Production, Delft University of Technology, Mekelweg 2, NL-2628 CD Delft, NL; Technical University of Munich, Institute for Energy Systems, 85748 Garching, Germany; Bavarian Center for Applied Energy Research (ZAE Bayern), Walther-Meissner-Str. 6, 85748 Garching, Germany
Sven
Unterberger
Institute of Process Engineering and Power Plant Technology (IVD), University of Stuttgart, Pfaffenwaldring 23, D-70550, Stuttgart, Germany
Klaus R. G.
Hein
Institute of Process Engineering and Power Plant Technology (IVD), University of Stuttgart, Pfaffenwaldring 23, D-70550, Stuttgart, Germany
The thermal use of biomass or waste, compared to other renewable energy sources, represents a cheap and technically feasible option for contributing to the reduction of the CO2 emissions. Biomass co-firing activities, both in the retrofit and new plants, are expected to expand significantly in the world in the coming years and to contribute to the abovementioned goal. Within this paper different concepts of biomass co-utilization and their requirements for fuel preparation are presented. The effect of co-combustion on combustion, operation, emissions, and ash utilization is discussed for pulverized fuel furnaces and fluidized bed boilers. An overview of recent co-combustion activities in Germany and The Netherlands is given.
STUDY OF EMISSIONS FROM A COOKING RANGE
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M.
Moya
Departamento de Ingenieria Mecanica, Pontificia Universidad Catolica de Chile, Santiago, Chile
Juan de Dios
Rivera
Department of Mechanical and Metallurgical Engineering, Pontificia Universidad Católica de
Chile, Vicuña Mackenna 4860, Santiago de Chile
We study the effects of two design parameters on emission indices of a cooking range. The parameters are the distance between the burner head and the bottom of the pot, and the primary air ratio. We measured the NO and CO emissions and thermal efficiency of two burners of different heating capacity. The same batch of commercial propane was used in all the tests. Results show that increasing pot-to-burner distance decreases CO emissions and efficiency and increases NO emissions. The effect of reducing primary air is to increase CO and efficiency, and to decrease NO.
REBURN: A COLLABORATIVE APPROACH TO RESEARCH, TECHNOLOGICAL DEVELOPMENT, AND DEMONSTRATION IN EUROPE
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G.
Hesselmann
Mitsui Babcock Energy Limited, Technology, Porterfield Road, Renfrew, PA4 8DJ, Scotland
The reburn process has a number of attractive features making it a technology worthy of consideration for the reduction of NOx emissions from pulverized coal plant. The process was taken from the conceptual stage to plant demonstration, supported by the European Commission (ECSC, JOULE, and THERMIE). Pilot scale testing and CFD analysis were central to establishing the optimal process conditions for reburning and ensuring good mixing of the reburn fuel and overfire air. Gas reburn was successfully demonstrated at the 600 MWe Longannet Power Station, and the demonstration of coal reburn is imminent at the 320 MWe Vado Ligure Power Station.