Competitive formation of NO and N/sub 2/ from both the emission sources of NH/sub 3/ and coal char-bound nitrogen compounds during the combustion of coal

The objective of this study is to basically elucidate a kinetic mechanism of formation of N/sub 2/ as well as NO through coal-bound nitrogen compounds during the combustion of coal. Two series of fundamental researches are conducted: the homogeneous gas-phase formation of NO and N2 through NH/sub 3/ as a simulated model of volatile nitrogen compounds (volatile-N) evolved from coal investigated in a mixture of NH/sub 3/, H/sub 2/, O/sub 2/, and Ar in a tubular flow reactor; and a mathematical model proposed for the competitive formation of NO and N/sub 2/ from both the emission sources of NH/sub 3/ and coal char-bound nitrogen (char-N) during the heterogeneous packed-bed combustion of coal-char particles under a NH/sub 3//O/sub 2//Ar gas stream. The predictions of the proposed model are compared favorably with the experimental data for the transient formation and reduction of CO/sub 2/, CO, and NH/sub 3/, as well as of N/sub 2/ and NO. In addition, the relative contributions of volatile-NO (from volatile-N) and char-NO (from char-N) to total-NO emissions, and of volatile-N/sub 2/ and char-N/sub 2/ to total-N/sub 2/ emissions are revealed both theoretically and experimentally.