ACERC
Abstracts - 1998 |
ACERC
Abstracts - 1998 |
|
|
Research Area 4: Simulation/Validation |
Xu, H.; Smoot, L.D. and
Hill, S.C.
Energy & Fuels, 12:1278-1289, 1998.
Advanced reburning technology, which makes use of natural gas injection followed by ammonia injection, has proven to be an effective method for the removal of up to 85-95% of the NO in pulverized, coal-fired furnaces. This paper reports the development of a seven-step, 11-species reduced mechanism for the prediction of nitric oxide concentrations using advanced reburning from a 312-step, 50-species full mechanism. The derivation of the reduced mechanism is described, including the selection of the full mechanism, the development of the skeletal mechanism, and the selection of steady-state species. The predictions of the seven-step reduced mechanism are in good agreement with those of the full mechanism over a wide range of parameters, applicable to coal-based, gas-based, and oil-based combustion cases. Comparisons with three independent sets of experimental laminar data indicate that the reduced mechanism correctly predicts the observed trends, including the effects of temperature, the ratio of (NH3/NO)in, and concentrations of CO, CO2, O2, and H2O on NO reduction. The observed effects of CO on NH3 slip were also reliably predicted. Mechanistic consideration provides an explanation for the roles of the important radicals and species. Also, parametric studies of the effects of CO2 and H2O have been performed with the reduced mechanism. A maximum in NO reduction exists, which strongly depends on the concentrations of NOin, CO, and O2, the ratio of (NH3/NO)in, and temperature.
Webb, B.W.; McQuay, M.Q.;
Gera, D. and Bhatia, K.
1998 American-Japanese Flame Research Committee International Symposium,
Maui, Hawaii, October 11-15, 1998.
Industrial glass producers are increasingly faced with the need to balance glass production and quality with environmental concerns. This paper summarizes the results of a study whose objective was the exploration of several NOx reduction strategies proposed for use in industrial float glass furnaces. The technologies included the introduction of an oxygen lance to simulate staged combustion, and oxygen/fuel firing. As a secondary investigation, the influence of soot on furnace operation was also explored. These strategies were compared by simulating numerically the turbulent reacting flow and heat transfer in the industrial environment of a full-scale float glass furnace. They were compared on the basis of four figures of merit: 1) fuel utilization efficiency, 2) combustion efficiency, 3) radiative heat flux uniformity on the glass melt surface, and 4) NOx evolution in the combustion gases.
McQuay, M.Q.; Webb, B.W.
and Baukal, C.E.
1998 American-Japanese Flame Research Committee International Symposium,
Maui, Hawaii, October 11-15, 1998.
The objective of the work reported here was to characterize the pre-rebuilt combustion performance in the natural-gas-fired, partially oxygen-enriched, aluminum-recycling furnace (Furnace 8) operated by Roth Brothers Smelting Corporation in Syracuse, New York. Measurements of gas temperature and species concentration (O2, CO, NO, and CO2) were made in the exhaust of the furnace. Local gas temperature, species concentration, incident wall radiant flux and furnace wall temperature measurements were also made in the combustion space.
|