OCR Text |
Show Heterogeneous Char N -NO Char + NO -N2 No + CO char -N2 For the gas, oil, and coal fuel results presented in table 2, it is expected that the levels of soot and char in the NO reduction zone will be quite different. The correspondence of NO reductions for the different fuel types suggest that the gas-phase processes might be dominating the NO reduction with the heterogeneous processes only contributing in a secondary manner. However, it is possible that, in the case of oil or coal fuel, heterogeneous NO reduction processes become more significant and homogeneous processes become less significant, leading to the same overall percent NO reduction as observed for gas fuel. Certainly, homogeneous processes are dominant in the case of gaseous fuels. Presently, data analyses and further experiments are underway to help define the mechanisms and rates of the fuel-staging process and to identify the relative significance of the homogeneous and heterogeneous NO reduction paths. ACKNOWLEDGMENT This work was supported by the Department of Energy, Pittsburgh Energy Technology Center (DOE Contract PC30296/6). J. Hickerson is the Project Officer. REFERENCES 1. Lim, J. J., et al., "Environmental Assessment of Utility Boiler Combustion Modification N0X Control," Acurex Draft Report TR/78-105, April 1978. 2. Wendt, J. 0. L., et al., "Pollutant Control through Staged Combustion of Pulverized Coal," U.S. Department of Energy Report FE-1817-4, February 1978. 8-22 |