Characterization of Coal Burnout in the Raceway of an Ironmaking Blast Furnace

Pulverized coal injection (PCI) is widely operated in ironmaking blast furnace (BF). In the past, coal burnout was usually characterized along tuyere axis due to technical difficulties, rather than the whole raceway surface. Recently, a three-dimensional (3D) PCI model included a 3D raceway and the combustion of two different fuels-pulverized coal and coke, allowing for calculating coal burnout over the whole raceway surface, in addition to along the tuyere axis. In this paper, in order to confirm whether the coal burnout tendencies at the two locations are consistent or not for the changes of a range of key operational variables, the influences of key PCI-related variables on coal burnouts is overviewed and compared at the two different locations. The comparisons show that the tendency of coal burnout over the whole raceway surface is largely inconsistent with those at the end of raceway along tuyere axis for the changes of key operational variables, and thus the latter cannot fully represent coal burnout in the raceway. For this reason, the former should be employed in the future when examining the combustibility of specific coals under BF conditions.