Kinetic Modeling of Fuel-Nitrogen Conversion in One-Dimensional, Pulverized-Coal Flames

Abstract

Abstract A detailed reaction mechanism for converting fuel nitrogen to nitric oxide and molecular nitrogen in gas flames is used to model nitrogen chemistry in fuel-rich coal-dust/oxidizer flat flames. In the devolatilization zone a simplified pyrolysis model is used and a hydrocarbon oxidation scheme supplement the nitrogen reactions. The predicted distributions of nitrogenous species (HCN, NH3, NO and N2) are compared to time-resolved experimental data obtained for two stoichiometrics and coal-types. The model accounts for the radical removal on particle surfaces, and various heterogeneous reactions for reduction of NO are considered. In the devolatilization flame zone the coal-N conversion mechanisms appear to be augmented by physical and chemical processes occurring in the vicmity of the devolatilizing particles. The current analysis supported by other investigations indicate that processes such as formation of fuel-rich volatile clouds and heterogeneous reduction of NO on surfaces of coal-particles a...