Numerical simulation of flow characteristics of side-bottom combined blowing in iron bath reactor

A numerical model of an iron bath smelting reduction furnace with side-bottom combined blowing was established to study the influence of blowing arrangements on the stirring effect of the molten pool, and the accuracy of numerical simulation was verified by water model experiment. By comparing the flow field of molten pool with single nozzle, double nozzles (symmetrical and asymmetrical), and four nozzles (symmetrical and asymmetrical), the proportion of dead zone, average turbulent kinetic energy, and mixing time, the results show that asymmetrical bottom blowing is better than symmetrical bottom blowing, and the effect of double nozzles bottom blowing was better than that of four nozzles bottom blowing. The mixing effect is the worst under the condition of single nozzle. When the bottom blowing is asymmetrical with double nozzles, the mixing time is the shortest. Under the condition of double nozzles asymmetrical bottom blowing, when the insertion angle and depth of side lance are larger and deeper, the velocity streamline of molten slag layer is denser and the value is larger; meanwhile, the reflux of molten iron layer is larger, the proportion of dead zone is smaller, and the whole molten pool is fully stirred. When the insertion depth of the side lance is deeper, the gas holdup in the molten pool is greater and the stirring of the molten pool is more intense, while the insertion angle has little effect on the gas holdup. By comparing the influence of different side blowing conditions on the slag layer, it is found that the slag layer is divided into two layers by double-layer side lance, with the critical surface of the slag layer at about 200–260 mm from the bottom, and the insertion depth of the lower side lance has a greater influence on the layering of the slag.