The Formation Of Nitric Oxide And The Detection Of Hcn In Premixed Hydrocarbon Air Flames At 1 Atmosphere

The NO concentration profiles of premixed hydrocarbon-air flames were measured using probe sampling and ultraviolet absorption of NO. The flames were stabilized on a Meker-type burner of 7 cm diameter at a pressure of 1 atm. Investigated fuels were CH4, C2H6, C2H4, C2H2, C3H8, n-C4H10, n-C6H14, i-C8H18, C6H6, C6H12, and gasoline. The measurements show the formation of nitric oxide according to the Zeldovich mechanism. In fuel rich flames the NO formation due to the Zeldovich mechanism would require unreasonably high concentrations of O atoms, and evidence is given for another way of NO formation in these flames. HCN has been found as an intermediate species and exceeds the NO concentration in very fuel rich flames. (Modified author abstract).