Article ID: ISIJINT-2025-202
In the blast furnace hearth, molten iron and slag accumulate in the coke packed bed and are drained from the tap hole. However, if the tapping rate is reduced, these melts accumulate and an increase in the gas pressure drop occurs. This leads to furnace trouble such as burden hanging. In this paper, the cause of the increase in gas pressure drop due to the accumulation of the melt was clarified phenomenologically using cold model experiments and numerical simulation.
As the result, it was proven that the gas flow region shrinks due to the accumulation of the melt, and the gas flow velocity near the tuyere increases. A numerical simulation of an actual blast furnace also showed that gas pressure drop increased rapidly when the average liquid level was within 1 m from the tuyere. If the average liquid level increases to the vicinity of the tuyere, the shape of the molten slag surface changes due to the gas pressure gradient, and the liquid level decreases on the tuyere side. Therefore, when the gas pressure drop due to the accumulation of molten slag increases rapidly in an actual blast furnace, it is necessary to reduce the blast volume and increase the tapping rate as soon as possible.
