Combustion Characteristics of Low Calorific Value Biogas and Reaction Path of Nox Based on Sensitivity Analysis

Although, biomass energy is a renewable energy are gradually advocating and studying widely, it is urgent to develop efficient biomass technology and reduce NOx emissions. The combustion mechanism of biogas mixture is unclear, which leads to the lack of basis for the control of operating parameters. Combustion characteristics and reaction path of typical low calorific value biogas with variation of preheating temperature and air equivalence ratio (Φ) are discussed. With the increase of preheating temperature, the final flame temperature moves up. Preheating of biogas can not only improve the flame propagation speed and flame temperature, but also increase the proportion of NO in the product at the end of combustion flame. To some extent, improving combustion efficiency and NOx control are contradictory in operating parameters. The amount of NO formation increases with the increase of flame distance. The maximum value of NO appears when Φ is 1.1. NO formation rate is improved by preheating of the biogas. The paths of N 2 → N 2 O →NO, N 2 → NNH →NO and N 2 →NO) are all enhanced. When the equivalence ratio changes from 1.0 to 0.8, the NO formation rates of the three reaction paths decrease