Numerical Simulation of Burden and Gas Distributions Inside COREX Shaft Furnace

Shaft furnace plays a very important role in the quantity and quality indexes of the COREX process. However, the simulation on the burden and gas distributions in COREX shaft furnace is still immature and hence needs further developed and improved. For instance, currently the geometric model is commonly used to simulate the COREX shaft furnace, but can only take into account one or two kinds of burden materials. To improve the simulation of the COREX shaft furnace, a three dimensional model of COREX shaft furnace is developed in this study. It applies the discrete element method (DEM) to a COREX-3000 shaft furnace with the charging system whose size is the same as the actual one. The model simulates the charging process with four types of burdens together and then is used to investigate the effects of different distributor angles on the burden and gas distributions. Results show that the position of burden apex moves towards the wall and the height of burden profile decreases with the increase of distributor angle. Coke and flux roll away from the striking point, while ore segregates close to the striking point, and pellet always tends to move towards the central area. Coke and flux segregate more obviously in the wall area when the distributor angle is no larger than 10°while they segregate more in both the wall and the center areas when the angle is no smaller than 20°. The distributor angle is recommended to be no larger than 10°to control the central gas flow and be larger than 25°to prevent the peripheral gas from over developing