ACERC
Abstracts - 1990 |
ACERC
Abstracts - 1990 |
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Thrust Area 6: Model Evaluation Data and Process Strategies |
Nichols, K.M.; Hedman, P.O.
and Blackham, A.U.
Fuel, 69, 1339-1344, 1990. Funded by US Department of Energy and Morgantown
Energy Technology Center.
Measurements of NO during laboratory-scale gasification of a Utah bituminous coal verified that small increases in pressure (from 1 to 2 atm) at constant residence time resulted in dramatic decreases in effluent NO levels. Tests were conducted at 3 target levels of pressure (1, 2 and 4 atm) and 2 target levels of residence time (450 and 900 ms). Oxygen-to-coal ratio for all tests was 0.90 (stoichiometric ration SR=0.45). The dominant factor in causing lower effluent NO levels was the increased kinetic rate of NO decay. Increased residence time in the fuel-rich gasifier contributed to lower effluent NO levels, but was of minor importance when compared to the effect of pressure on the decay rate. Concentrations of N2 appeared to be slightly increased and concentrations of total fuel nitrogen (TFN) decreased as pressure was increased. Also, concentrations of N2 increased and concentrations TFN decreased as residence time was increased at 1 atm pressure. For all tests, nitrogen conversion exceeded carbon conversion by about 10%. Neither nitrogen conversion nor carbon conversion was found to increase with increasing pressure. Both increased slightly (4-5%) with increasing residence time, evidence that most of the coal nitrogen and carbon was released during devolatilization.
Cannon, J.N.; Webb, B.W.
and Queiroz, M.
14th Annual Energy-Sources and Technology Conference and Exhibition,
Houston, Texas, 1990. Funded by ACERC and Empire State Electrical Energy Research
Corp.
Brigham Young University (BYU)/ACERC testing of an 80 MWe corner fired coal power plant in June of 1989 sought data to validate 3-D comprehensive combustion computer codes. The major controlled variables during the two weeks of testing were coal grind fineness, O2 content in the flue-gas, plant load, and burner tilt.
A full complement of board data was taken along with coal fineness, coal split between coal feed lines and on-line trial instruments on carbon-in-ash and air flows. Selective spatially resolved data was collected throughout the radiant section of the boiler from the near field in the burners to the platen area with water cooled probes for gas temperature, gas composition, particle size distribution and composition, velocity (magnitude, direction and turbulence) measurements, and radiant flux.
The water cooled probe results yielded spatially resolved data in the near and far combustion field that will be compared to computer modeling runs in the future at BYU. The effects of O2, coal fineness, load variation and burner tilt are clearly discernable on the spatially resolved gas temperature, gas composition, velocity, radiant flux and particle size and composition measurements and are reviewed in this paper. Centrifugal effects on particle size are also discernable as are particle size effects on composition.
Boyack, K.W.
Ninth International Congress on Applications of Lasers and Electro-Optics:
Symposium on Optical Methods in Flow and Particle Diagnostics, Boston, Massachusetts,
1990. Funded by Kevin Boyack and ACERC.
Several multi-color CARS approaches have been recently demonstrated. One of these approaches, dual-Stokes CARS, is a straight-forward addition of two single-color CARS processes. This approach has been used to take simultaneous single-pulse measurements of temperature and mass fractions of N2, CO, O2 and CO2 in turbulent nonpremixed jet flames of CO/N2. The simultaneous measurement of all major species allows the nonresonant susceptibility of the mixture to be calculated directly rather than assumed, thus eliminating a potential source of error in the measurements. The measurement of all major species also allows calculation of the mixture fraction, defined as the local mass fraction of fluid originating from the primary stream. Direct measurement of the mixture fraction is very useful as it is necessary for the accurate modeling of turbulent reacting flows.
The accuracy of the Brigham Young University dual-Stokes CARS instrument has been determined by performing calibration measurements over flat flames of CO/N2 of known composition. This has shown that measurement of four species using CARS is possible and sufficiently accurate to justify use of the technique in the characterization of turbulent flames. Measurements were then taken in turbulent nonpremixed jet flames of the same fuel, which directly demonstrate the applicability of the instrument to turbulent reacting flows. A sample of data from more extensive measurements in turbulent nonpremixed jet flames is also given to show the extent to which multiple species CARS has been employed.
Boyack, K.W. and Hedman,
P.O.
Twenty-third Symposium (International) on Combustion, The Combustion
Institute, Pittsburgh, PA, 1990. Funded by ACERC.
A dual-Stokes coherent anti-Stokes Raman scattering (CARS) instrument has been used to make simultaneous time- and space-resolved measurements of temperature and the mass fractions of N2, CO, O2, and CO2. Calculation of the mixture fraction, a conserved scalar, is possible for each data point, making the technique useful in turbulent combustion environments. The viability of this instrumental approach has been demonstrated by calibrations in laminar CO/N2 flat flames of many different stoichiometries. Maximum single-shot rms values due to instrument fluctuations are attained in near stoichiometric mixtures and are ±45 K for temperature, ±0.042 for YN2 and YCO2, ±0.015 for YO2 and YCO, and ±0.036 for mixture fraction.
Measurements have been made using this instrument in turbulent nonpremixed jet flames of CO/N2 with small amounts of H2. These measurements demonstrated that for turbulent systems, limitations are imposed on the CARS technique due to insufficient dynamic range and image persistence problems with the intensified photodiode array (IPDA) detector. These limitations are minimized with proper experimental parameters and data correction methods.
Cannon, J.N.; Queiroz, M.
and Webb, B.W.
Symposium on Effects of Coal Quality on Power Plants, Sponsored by Electric
Power Research Institute, St. Louis, MO, 1990. Funded by ACERC and Empire State
Electrical Energy Research Corp.
The major thrust of this paper is to present the data from research type instrumentation used to probe a full-scale utility boiler. The results will be used to validate Comprehensive Combustion Codes (CCC). This paper reviews how CCC can be integrated into the Coal Quality Impact Model (CQIM) to assist in accuracy. The paper presents selected portions of the spatially resolved gas velocity, gas temperatures, and composition profiles, radiation plus particle size, velocity, and concentration profiles for common sample ports to allow data comparison between data sets. The data are analyzed to show the effects of coal particle grind, load, burner tile, and excess air.
The data show particle burnout time, centrifugal force influence on the particles, near burner field effects as distinguished from far field effects, incident radiation imbalance due to coal pipe splits, and load changes on heat transfer surfaces and flow field. In addition, a full set of operator board data was taken to connect the research results to standard utility operating instrumentation.
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