Variation in Multiphase Flow Characteristics by Single-Flow Post-combustion Oxygen Lance Blowing in BOF Steelmaking

In converter steelmaking, the impact of a high-speed gas jet on the melt pool is a complex process in which the shape of the impacted cavity has an important influence on the smelting. Therefore, this paper establishes a full-size model of the traditional oxygen lance (TL) and post-combustion oxygen lance (PCL) in a 250 t converter to analyze the fluctuation of the slag–metal interface, the shape of the impact crater, and the change of the fluid flow in the melt pool. The study shows that the melt pool surface maintains a stable vibration state over time. The impact diameter and impact depth of the PCL are 16 and 20 pct greater than those of the TL. A model for predicting the depth of the PCL impact crater is also proposed, and the numerical simulation results agree well with the model results. The industrial tests have shown that, compared to the TL, the PCL increases the converter temperature by 27.3 °C, which increases the oxygen supply intensity with maintaining the regular blowing and shortens the oxygen supply time by 78 seconds.