Numerical study of an 870MW wall-fired boiler using De-NOx burners and an air staging system for low rank coal

Abstract

Pulverized coal-fired boilers have been used for power generation in Korea for decades. Recently, an 870-MW wall-fired boiler with De-NO x TM burners and an air staging system was constructed for use with low-rank coal. The results of a full-scale simulation of its combustion characteristics agreed well with measurements obtained under normal operating conditions for temperature, unburned carbon, and nitric oxide. Contrasting trends in unburned carbon and NOx emissions were observed, depending on the particle size and the location of the standby burner within the boiler. Combustion was also found to shift forward with small particle sizes and backward with large particle sizes. The results of a Thermo-mechanical analysis (TMA) indicated that the actual sticking temperature was lower than that suggested by the initial deformation temperature (ASTM) criteria. A logistic function was used to describe TMA shrinkage. Locations subject to high deposition potential were predicted with reference to soot-blowing phenomena.