Reduction of nitrogen oxides formation during gas burning

The aim of this work is to investigate the influence of two staged gas firing on NOx formation in the furnace. One of the main toxic substances formed during gas firing are nitrogen oxides (NOx). Reduction of nitrogen oxides formation can be organised in several ways. One of the way - is to organise the staged combustion. Influence of two staged gas firing on the formation of nitrogen oxides was investigated using two staged gas injection scheme. Investigations were carried out on specially constructed 80 kW capacity laboratory stand. Introduction of two staged firing allowed to reduce NOx emissions significantly without worsening the economical results of the combustion. Influence of primary and secondary gas ration and the secondary gas inlet place on the formation of nitrogen oxides was determined in this work. In comparison with single stage gas firing, NOx concentration was reduced by 4-5 times using two staged gas firing. Effect of NOx concentration reduction depends on distribution of gas into two streams as well as on distance of the secondary gas inlet from the embrasure of the burner. Due to the excessive amount of air in the first zone, the combustion temperature falls down, what consequently suppress formation of thermal NOx.