Improvement of low load combustion stability for advanced low NOx burner

The combustion technology which carries out both low NO, emission and low load stable combustion is desired in pulverized coal-fired power plants. A new advanced low NOx burner which can reduce NOx concentration and unburned carbon concentration in fly ash to 100 ppm and 3% respectively, had already been developed. To improve the combustion stability of this burner at lower loads, an adjustment method to raise the local concentration of coal by placing a ring in the primary air nozzle was invented. The combustion stability and the emission characteristics of NOx and unburned carbon in flp ash were investigated with a test furnace having a coal feed rate of 100 kg/h. The burner equipped with a ring achieves stable combustion at 20% load as like an oil burner by the adjustment of the local coal concentration. At higher load, the burner equipped with a ring maintains the same emission characteristics of NOx and unburned carbon in fly ash with the new advanced low NOx burner.