1993 Volume 19 Issue 2 Pages 169-174
The gas-phase formation of NO, N2O and HCN through NH3 in gas systems with coexisting CH4 was investigated experimentally in a tubular-flow reactor.
Experiments were conducted for NO/CH4/O2/Ar, NH3/CH4/O2/Ar and NH3/NO/ CH4/O2/Ar gas reaction systems at temperatures of 1143-1293K, with the initialconcentration of O2 and CH4 being lower than 3.0 vol %.
It was found within the range of the present experimental conditions that : 1) The main product of the decomposition of NH3 was N2 in addition to NO, N2O and HCN, when the decomposition of CH4 was sufficient. 2) The concentrations of the produced NO, HCN and N2O depended on the ratio of the concentrations [O2] 0/ [CH4] 0 in the NH3/CH4/O2/Ar gas system. In the range of [O2] 0/ [CH4] 0 <1.0, the formation of HCN and of N2O were enhanced with an increase in the ratio of [O2] 0/ [CH4] 0, and formation of NO was inhibited. On the contrary, in the range of [O2] 0/ [CH4] 0>1.0, the changes in HCN, N2O and NO concentration show an opposite tendency to those observed in [O2] 0/ [CH4] 0 <1.0. 3) HCN of high concentration was formed by adding NO or NH3 to CH4 /O2 /Ar gas system.
