Formation and Control of Nitric Oxide from Fuel Nitrogen : 2nd Report, Formation and Decomposition of Fuel-NO in Diffusion Flames

Abstract

Problems in the formation mechanism of fuel-NO in diffusion flames are researched by adding ammonia or nitric oxide to fuel or combustion air. conversion ratios of ammonia to nitric oxide in diffusion flames are lower than those in premixed flames because added ammonia is decomposed in fuel-rich region near the inner flame surface. Conversion ratios are strongly affected by the amount of air included in fuel. Formation processes of fuel-NO in hydrogen diffusion flames can be explained by reaction scheme based on extended Zeldovich mechanism as well as in premixed flames if an assumption is made that fuel-N decays finally into N atom. Decomposition reaction of added NO plays a very important role in methane diffusion flames.