Study On Influence Of Pulverized Coal Characters On NO Reduction By Reburning

In the thesis detailed mechanism about NO reduction by pulverized coal reburning is discussed, reactions between volatiles and NO and the relevant mechanism are analyzed. Homogeneous reactions between CHi, NHi, HCN, HCCO and NO and heterogeneous reactions catalyzed by char are considered as the dominating NO reduction reactions. The physical and chemical characters of four different size of pulverized coal are studied. It is showed that the finer pulverized coal has better burn out characters, and its char has more extensive surface area. Mathematical models with elementary reactions that based on entrained flow is developed, the reburning process of pulverized coal of various size is studied by numerical simulation and the simulation results nearly are consistent with the experimental results. The simulation results about the changing process of several important species during the pulverized coal reburning are analyzed. The simulation results indicate that finer pulverized coal can be heated up faster, more volatiles can be produced and they can be released faster from finer pulverized coal; also the finer pulverized coal reburning can attain more NO reduction.