Abstract
The paper deals with the experimental investigation of combustion operating parameters and burner’s constructional parameters on the formation of nitrogen oxides. The tests were performed using the burner prototype with the maximal capacity of 1.5 MW. The burner is both fuel-staged and air-staged. During the testing campaign, various geometries of secondary nozzles and their position towards the burner quarl, and various geometries of the so-called swirl generator were investigated. The observed parameters included NOx and CO emissions, turndown ratio, flame stability, flame length and flame shape, heat transfer from hot flue gas to the combustion chamber’s shell and the distribution of in-flame temperatures measured in the horizontal symmetry plane of the chamber.
The results showed that in cases when the minimum of NOx emissions was reached, the flame instability was observed. When the length of flame was about 4 m, the NOx emissions were low too, however, the heat transfer in the radiation section significantly decreased. Better results were obtained when the flame length was up to 2 m at the maximal burner capacity and the primary stage was highly fuel-lean while the balance of fuel was combusted in the secondary stage. The minimum NOx was about 30 ppm.
