The effect of pulverized coal injection and volatile matter content of coal on combustion characteristics around the raceway zone in the blast furnace

A two-dimensional mathematical model is developed to describe transport phenomena in a packed bedof coke in front of a blast furnace tuyere with and without pulverized coal injection (PCI). The model consists of two submodels: one is a pulverized coal (PC) combustion model in the blowpipe and the other is a combustion model in the packed bed of coke where the thermal radiation is considered. In this model, coke particles in the raceway are treated as a continuous phase, and both phases of gas and coke particles are calculated by using the Eulerian approach. This model is applied to practical operating conditions in the blast furnace. As the residence time of PCparticles in the blowpipe is quite short, its burn-off in the blowpipe is very small, and the PC particles mainly burn in the raceway cavity. While the burn-off of PC particle increases with the volatile matter content, some particles reach the inner wall of tuyere when high-volatile coal is used. When PC is injected into tuyere, more oxygen is consumed, and a higher temperature rise appears at the region closer to the tuyere tip in the raceway than those of all coke operation. The temperature profiles in the raceway with PCI and without PCI are different from each other due to the difference of flow regime.