Effects of Tuyere Dimensions and Bosh Angle on Raceway Shape and Particle Movement Based on Cold-Model Experiments

摘要

To curb CO2 gas emissions from steel plants, there is an urgent need to decrease the reducing agent ratio (RAR). Theoretically, other than the conversion of materials and reducing agent of blast furnace, the most important countermeasures are to increase the gas utilization efficiency (shaft efficiency) and to decrease the heat loss. To increase the gas utilization efficiency and to decrease the heat loss caused by the drop in gas velocity in the periphery, it is necessary to improve the gas permeability of the blast furnace, which depends mainly on the properties of the burden materials. In addition, optimizing the tuyere dimensions and bosh angle may improve the permeability in the lower part. A 1/10-scale cold-model with two tuyeres has been developed, based on which the effects of tuyere dimensions, such as nose length and nose angle, and bosh angle on the raceway were investigated by using particle image velocimetry (PIV) and an infrared thermo-viewer. Experimental results show that a long tuyere improves the circulation of particles in the raceway and the heat transfer of the deadman. Raceway depth does not change for tuyere angles between +20 and –20 degrees, but a downward tuyere improves the heat transfer in the deadman. Although a large bosh angle helps to smooth the descent of coke, it accelerates peripheral gas flow and increases heat loss.