Effect of Oxygen Lance Structure on the Flow Field in the 100t K-OBM Converter

Abstract

The dynamic condition of the molten bath in a combined-blowing converter was decided by the operational parameters of the oxygen lance and bottom-blowing nozzle. Based on the movement directions of the kinetic energy sources generated by the top-blowing multi-jets and bottom-blowing bubbles, it could be inferred that these two sources created a kinetic energy cancellation phenomenon at the surface of the molten bath. Thus, the effect of three types of oxygen lance structures on the flow field of the molten bath in a 100t K-OBM (Klockner Oxygen Blowing Maxhütte) converter has been analyzed by a serious of water experiments and numerical simulations. The results indicated that the neutralization of kinetic energy significantly improved as the top-blowing flow rate increased from 7200 to 9600 Nm³/h, leading to an extended mixing time. Meanwhile, in contrast to the traditional BOF converter, the K-OBM converter exhibited a noticeable reduction in top-blowing intensity and a significant enhancement in bottom-blowing intensity. Consequently, the variation in the average velocity of the molten bath generated by the three types of oxygen lances gradually decreased as the depth of the molten bath increased. Based on the results of industrial application, 2# lance is designated as the optimal oxygen lance for the K-OBM steelmaking process, which achieved the highest dephosphorization rate, the shortest melting time and the lowest T. Fe content, comparing with the original lance and #1 lance.