Numerical simulation of gas blowing effect on powder injection desulfurization during RH refining process

In order to study the influence of gas injection parameters on the powder injection desulfurization during RH refining process and improve the efficiency of desulfurization, three-dimensional coupled k-ε turbulence model, volume of fluid (VOF) model, discrete phase model (DPM), user defined scaler (UDS), and unreacted core desulfurization kinetic model were established based on the powder injection desulfurization process of an actual 230 t RH. The effects of the circulation flow rate of snorkel, injection at the vacuum chamber side, and injection at the ladle bottom on the speed and powder injection desulfurization of molten steel were discussed. The results show that the desulfurizers are mainly concentrated on the interface of vacuum chamber near the downleg side after it is sprayed into the vacuum chamber, and desulfurizers enter the ladle from the downleg with the circulating flow of molten steel. The desulfurizers in the ladle also tend to accumulate on the downleg side. The speed and desulfurization rate of molten steel increase with the increase of the circulation flow rate of snorkel, but the increase is small when the circulation flow rate (standard condition) increases from 1 000 L/min to 2 000 L/min. When the circulation flow rate continues to increase from 2 000 L/min to 3 000 L/min, the speed of molten steel increases significantly, but the end-point desulfurization efficiency only increases by 4.0%. The speed and desulfurization rate of molten steel increase slightly with the 2 000 L/min side injection at the vacuum chamber. When the gas injection with 200 L/min flow rate is carried out at the bottom of the ladle corresponding to the up snorkel, the speed of molten steel in the ladle increases significantly, but the desulfurization rate decreases due to the decrease of residence time for desulfurizer in the ladle. The study provides a theoretical basis for improving the efficiency of the powder injection desulfurization during RH refining process.