Three-Dimensional Mathematical Model of Multiphase Combustion in Full Oxygen Blast Furnace

The complicated combustion of pulverized coal, free coke and cycle gas in the raceway of full oxygen blast furnace (FOBF) is different from the process in a traditional blast furnace. The differences of free nitrogen, cycle gas mixture, increased coal rate and decreased blast temperature contribute to the complexity of reductive conditions with temperature and composition. A three-dimensional CFD model considering the processes in the regions of raceway, blowpipe, deadman and dropping-zone is developed to describe the kinetic, thermal and chemical behaviors of the fuel combustion. The qualitative and quantitative analysis is conducted to evaluate the effects of operating conditions including temperature of cycle gas, injecting rate and particle diameter of pulverized coal. Simulation results show that large amount of pulverized coal injection (PCI) and also cycle gas injection is feasible with the high oxygen concentration for oxygen blast furnace. The coal injecting rate is a sensitive parameter for the combustion effect in raceway and corresponding measures must be considered for the enhancement of PCI. FOBF process could construct stronger reductive atmosphere than traditional blast furnace, which is beneficial to improve the productivity.