NITRIC-OXIDE FORMATION FROM FUEL NITROGEN IN STAGED COMBUSTION - ROLES OF HCN AND NHI

Nitric oxide formation from fuel nitrogen (NH3) in staged combustion is investigated paying attention to NO, HCN, and NH3 formation in the fuel-rich first-stage combustion and the conversion of residual HCN and NH3 into NO in the second-stage combustion. Effects of operating conditions such as equivalence ratio, temperature level, fuel types, and amount of fuel nitrogen are examined experimentally. The characteristic difference of NO formation in staged combustion between hydrocarbon (C3H8) and nonhydrocarbon (CO + H2) flames is pointed out to be due to the fact that HCN is formed in the former flames but not in the latter and that the conversion of HCN into NO is much larger than that of NH3 in the second-stage combustion. The comprehensive interpretations of the experimental results are discussed by modeled chemical-kinetic calculations. © 1979.