On the fate of fuel nitrogen during coal char combustion

Authors

  • J. O. L. Wendt,

    Corresponding author
    1. Department of Chemical Engineering, University of Arizona, Tucson, Arizona 85721
    • Department of Chemical Engineering, University of Arizona, Tucson, Arizona 85721
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  • O. E. Schulze

    1. Department of Chemical Engineering, University of Arizona, Tucson, Arizona 85721
    Current affiliation:
    1. Dow Chemical Company, Freeport, Texas
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Abstract

The physical and chemical characteristics that influence the conversion of fuel nitrogen to nitrogen oxides during coal char combustion were theoretically examined by using a simplified model in which nitric oxide is an intermediate product between fuel nitrogen and N2.

It was found that diffusion-reaction interactions were important in determining the selectivity of the char particle toward nitric oxide production. At low temperature fluidized bed combustion conditions, pore size is important, and low conversion of fuel nitrogen to nitric oxide is favored by long narrow pores. Under high temperature, pulverized coal combustion conditions, the model provided insight into mechanisms of nitric oxide formation and predicted the observed weak temperature dependence of fuel nitrogen conversion, as well as a significant effect of particle size.

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