Nitric Oxide Emission from Diluted CH 4 /CO/H 2 Jet Diffusion Flames

The paper presents an experimental study of nitric oxides from jet diffusion flames with fuels being N 2 /CO 2 diluted gas mixtures of CH 4 /CO/H 2 with methane concentration in the range of 4-76% (vol.). The Froude number was varied in the range of 70-8250 and nozzle exit velocities in the range of 2-18 m/s with nozzle diameters of 4 and 6 mm.The results show that the total NO x emissions increase with increasing methane content in the gas mixture with a significant contribution of prompt NO x . The measured NO x emission index is in the range of 0.05-2.0 g NO x /kg fuel with a corresponding methane concentration in the gas mixture in the range of 4-76% (vol).The measured NO x emissions is found to be proportional to 1.36Fr ⋆3/5 , where Fr⋆ is a modified Froude number based on the volume fraction of fuel in the diluted gas mixture.