Mathematical modelling of flow and heat transfer in COREX process by CFDDEM method: The effect of a novel burden profile

Iron for steel production is produced mainly in a conventional blast furnace (BF). New ironmaking processes have been introduced in the last two decades because of environmental concerns to reduce CO2 emission. One such process is COREX, which can operate, at least in theory, without any need for coking-coal, significantly reducing emissions and costs. However, the complicated gas-solid flow inside the reduction shaft (RS) of COREX gives rise to operational difficulties such as sticking of particles at high temperature. Understanding the flow would enhance ability to control them and so improve overall process quality. To understand multiphase flow in the RS, mathematical modelling has been employed here, coupling discrete elements method (DEM) with computational fluid dynamics (CFD). Using this CFD-DEM approach, gas-solid flow and heat transfer phenomena were investigated at a particle level. The model was able to describe heat transfer inside the RS, and a novel burden distribution arrangement was examined, with some improvement in heat transfer in the central part of the furnace. While future analysis and investigation should deal with more realistic properties, these results confirm that mathematical modelling, and in particular CFDDEM, is an efficient tool for describing complicated phenomena inside the RS. The findings of this study should be useful for control and optimization of the RS operation.