The relative importance of homogeneous and heterogeneous mechanisms governing the destruction of chemically bound nitrogen during the fuel rich combustion of a Utah bituminous pulverized coal and its char was determined. Pulverized fuels were burned in a self sustaining but well characterized mode in a 15 cm ID downflow combustor. Measurements included time resolved profiles of major species, minor nitrogenous species and char nitrogen concentrations as well as (thermocouple) gas and (optical) particle temperatures. Data from fuel-rich char combustion studies (SR=0.8,0.4) show that concentrations of HCN and NH/sub 3/ in the post flame gases were small compared to the concentration of NO. NO destruction was found to be controlled by an heterogeneous mechanism involving the char carbon surface and this mechanism, which is deactivated by oxygen, was modeled, yielding rates consistent with those in the literature. The fuel rich coal combustion studies yielded profiles of high concentrations of HC, NO and NH/sub 3/. The decay of NO in the post flame was not consistent with the heterogeneous rate determined from the char data. Rather, the data show that reactions in the gas phase dominate and the global homogeneous kinetics equations given describe (with one exception) the post-flame nitrogenous species concentrations. This is consistent with the gas phase kinetics of Fenmore.