Kinetic Study of Promoted SNCR Process by Different Gas Additives

A detailed chemical kinetic model for promoted SNCR process by H₂, CO and CH₄ was developed based on recent studies. The model was validated by available experimental data. The influence of H₂, CO and CH₄ on SNCR process was investigated by chemical kinetics calculation. The results indicate that H₂ is more effective to lower SNCR temperature window than CO and CH₄. While the additives concentration is low, CH₄ is more effective than CO. But when the molar ratio of additives and initial NO exceeds 3, the effect of CO begins to catch up that of CH₄. The promotion mechanisms of them were identified through sensitivity and rate-of-production analysis. The effects of these additives on NO reduction are achieved principally by promoting the production of OH, O and H radicals. Besides the reaction of CH₃ radical with NO₂ enhances NO reduction at lower temperature when CH₄ additive is used.