Perspective on Progressive Development of Oxygen Blast Furnace for Energy Saving

The importance of energy saving in the ironmaking process is widely recognized. Many energy saving efforts related to ironmaking have already been carried out, and further energy savings by conventional methods are hardly to be expected. The oxygen blast furnace is considered to be a promising process in terms of flexibility of energy use and advantages related to CO2 mitigation. Focusing on energy saving, in this study, the optimum configuration of the ironmaking process based on the oxygen blast furnace was investigated by numerical approaches and case studies. First, because productivity can be greatly improved in the oxygen blast furnace, blast furnace inner volume can be reduced while maintaining the same production rate. Because the downsized oxygen blast furnace makes it possible to relax burden material strength requirements, energy consumption for agglomeration in the coke oven and sintering machine can also be reduced. Therefore, a DEM simulation was carried out to confirm the effect of the burden load reduction in the downsized condition. It was found that the compressive stress in the downsized oxygen blast furnace was 20-30% less than that in the conventional blast furnace. The energy flow in the ironmaking process was also investigated by using a material and energy balance model, considering the functions of an integrated steel works. It was found that the energy consumption of the ironmaking process based on the energy saving oxygen blast furnace could be reduced by 5.3% while maintaining the same energy supply to downstream processes.