The Effect of Particle Size on Combustion Characteristics of Pulverized High-Volatile Bituminous Coal

The particle size effect on the combustion characteristics of pulverized coal was investigated in the cylindrical-shape, horizontal furnace, fired in the range of 8.8∼10.6 kw. Three differently-sized fractions (5, 30, and 44 microns in average diameter) of high-volatile bituminous coal, were burned in the test furnace. Burnout behavior of pulverized coal flame were determined through the measurement of stable species concentrations (CO$_2$and H$_2$O). Concentrations of CO$_2$were compared with the theoretical values and the result showed good agreement. Thermal behavior of pulverized coal flame were determined as maximum flame temperatures occurred at fuel-rich conditions in every case. Flame lengths were also determined by decreasing with the particle size decrease. The flame length of the fine sized coal sample was comparable to that produced by distillate oil. The color of the coal flames ranged from orange to yellow, with the flame of the fine size fraction being brighter and yellower than the others.