CFD-DEM study of heat transfer in the reduction shaft of Corex

Corex has a great potential to produce hot metal economically and environmentally friendly. Reduction shaft (RS) for the direct reduction of iron ore is one of the two major reactors in Corex. This work uses a two-dimensional slot model to investigate the thermal behavior of the gas-solid flow in the RS by a combined computational fluid dynamics and discrete element method approach.The general heat transfer characteristics are firstly examined. The complicated transient gas-solid and heat transfer phenomena are demonstrated in the RS process. Then, the effects of discharge rate and two common burden profiles are investigated qualitatively. The results show a linear relation between the steady state bed temperature and discharge rate, which could be helpful for the construction of a reliable scaled down discrete particle model of the RS. The difference between the temperature distributions for two burden profiles is illustrated, which indicates that the control of burden profile could be an effective method to improve energy efficiency. These findings should be useful for the control and optimization of the RS operation.