Side-blowing optimization of electric arc furnace based on gas-liquid-solid three-phase flow simulation

Consteel electric arc furnace (EAF) is a high-efficiency, green and low-carbon steelmaking equipment widely used in China, and its molten pool stirring process has an important influence on smelting. Most of them are equipped with side-blowing technology, while a few feature bottom-blowing systems. The side-blowing oxygen lances (or burners) play a key role in improving the uniformity of the molten pool in addition to cutting scrap steel and eliminating cold spots. To enhance the flow and mixing efficiency of molten steel, this paper simulates the impact of the side-blowing process on the flow field within the molten pool based on gas-liquid-solid three-phase flow. A hydraulic model with a similarity ratio of 1∶8 was made based on a 150 t Consteel EAF and its side-blowing oxygen lances. Referring to fluid mechanics theory, a side-blowing arrangement with non-uniform gas flow was proposed. Simulated tests were then conducted to study the movement behavior of gas-liquid-solid three-phase flow and the melting phenomenon of scrap simulants under different side-blowing conditions. The average mixing time, flow field movement and melting of scrap simulants were used as criteria to obtain the preferred non-uniform gas volume arrangement scheme. The results show that a 10° horizontal deflection of the simulated side-blowing oxygen lances is the optimal angle in this study. At a horizontal deflection of 10°, increasing the side-blowing gas volume is more conducive to mixing. However, when the gas volume is large, the reduction in average mixing time caused by increasing the same gas volume is significantly reduced, and the gas energy utilization rate decreases. Under a certain side-blowing intensity, when increasing the total side-blowing gas volume, concentrating the gas volume increase on one specific side-blowing lance is more conducive to mixing than uniformly increasing the gas volume of each lance. Under the S4 condition of this study, the No.4 side-blowing lance is located at the junction of two cold zones, the feeding zone and the eccentric bottom tapping(EBT) zone. Under the same gas volume, this configuration achieves the shortest average mixing time and increases the gas utilization rate by 15%. At this time, the liquid phase mixing and scrap simulant movement speed are faster. Meanwhile, the amount of scrap entering the cold zones decreases, and the accumulation and bonding phenomena are significantly alleviated. Overall, this is the preferred non-uniform arrangement. The results of this experimental study provide reference and guidance for the position adjustment and process parameter optimization of actual side-blowing oxygen lances in EAFs.