STUDY OF HIGH-TEMPERATURE GAS REACTION OF NO-CH4-O2(-CO2) MIXTURES BY MEANS OF A MOLECULAR-BEAM SAMPLING-MASS FILTER SYSTEM

The homogeneous gas phase reaction of NO-CH4-O2(-CO2)-Ar mixtures in high temperature is investigated by means of the molecular beam sampling method. The reaction species NO, CH4, HCN, CO, CO2and N2are quantitatively analyzed with a mass filter system within a limit of 10 ppm. The species resulting from NO reduction are HCN, NH3and N2. The amount of HCN decreases with an increase in the ratio of O2to CH4. Both NO reduction and formation of HCN, NH3and N2are clearly enhanced by the addition of CO2. Conversely, the consumption of O2is retarded. In these reactions, it appears that oxidation of CH4initiates the NO reduction and, therefore, HCN, NH3and N2are progressively formed. Based on the experimental results, an overall kinetic equation for HCN behavior associated to NO reduction is derived as follows: d[HCN] ;—i = 0.4(0.75[NO][O2]1/2)- 1.17 x 10-3[HCN][CO2] dt The effect of CO2addition on the present reactions is in agreement with a reaction mechanism proposed earlier by Haynes. © 1979 Taylor & Francis Group, LLC