Solid Flow in a Shaft Furnace in Smelting Reduction Process under Circumferential Imbalance Conditions

Smelting reduction process is a promising technology that produces liquid iron with the advantages of a reduction in costs and a reduction in adverse effects on the environment. In this work, a three-dimensional DEM-based model is used to investigate solid flow in a shaft furnace under circumferential imbalance conditions. The results confirm that under the abnormal conditions, where several inactive screws are adjacent to each other, the solid flow patterns change significantly. A large stagnant zone forms above the inactive screws, and the stagnant zone volume and interactive force increase with an increasing number of inactive screws. The average descending velocity, stagnant zone volume, and interactive force in separated inactive conditions are lower than that in adjacent inactive conditions when the number of inactive screws is the same. Increasing the rotation speed of active screws that are located near the inactive screws can decrease the stagnant zone volume and particle interactive force in shaft furnace. Therefore, adjusting the screw speed of active screws near inactive screws is an effective method for reducing the imbalance impact. The findings of this work are useful for the control and optimization of the operation of shaft furnace.