Effect of the Injection Angle of Reducing Gas on Coal Flow and Combustion in a 50% Oxygen Blast Furnace

Medium oxygen-enriched blast furnace that utilizes reducing gas injections is a feasible new ironmaking process that can significantly reduce the coke ratio and carbon dioxide emissions. In this study, a three-dimensional numerical model of lance-blowpipe-tuyere-raceway zone was established, which was used to study the influence of the reducing gas injection angle (30-70 degrees) on the flow and combustion of pulverized coal in a new tuyere of the 50% oxygen blast furnace. As the injection angle increases, the tuyere kinetic energy first decreases and then increases, and the pulverized coal combustion efficiency increases. Compared with the injection at 30 degrees, the coal particle temperature under the injection conditions of 70 degrees at the raceway outlet increased by 326 K, and the char conversion ratio and the burnout increased by 27.4% and 22.4%, respectively. However, it is worth noting that under the high injection angle, local high temperature appears on the tuyere wall, which requires cooling to avoid damage to the tuyere in the actual blast furnace.