HOMOGENEOUS NITROUS-OXIDE FORMATION AND DESTRUCTION UNDER COMBUSTION CONDITIONS

N2O decomposition and formation during the oxidation of NH3 and HCN were studied in a quartz flow reactor in the presence of CO, NO and other gases. The emphasis is on the influence of CO and NO. In addition, the homogeneous nitrogen chemistry of fluidized bed combustion and the selective noncatalytic reduction of NO (SNR) are discussed. The rate of N2O decomposition in N2 agrees with a first-order rate expression. The presence of CO or H-2 increases the decomposition rate regardless of the additional presence of O2. For the formation of N2O, HCN oxidation is more efficient than NH3 oxidation. The presence of NO increases the amount of N2O formed during the oxidation of HCN or NH3. CO moves the N2O formation toward lower temperatures. H2O increases the reaction rate where few components are present, whereas H2O has little influence in the presence of large amounts of a combustible component such as CO. There are indications that NO is a necessary intermediate for any significant formation of N2O during the oxidation of NH3 and HCN. NO reduction is obtained when NO is initially present during oxidation of both NH3 and HCN. These results are comparable to the respective SNR results with reductant ammonia and urea.