Improvement of Low Load Combustion Stability for Advanced Low NOx Burner.

Abstract

The combustion technology which carries out both low NO x emission and low load stable combustion is desired in pulverized coal-fired power plants. A new advanced low NO x burner which can reduce NO x 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 NO x and unburned carbon in fly 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 NO x and unburned carbon in fly ash with the new advanced low NO x burner.