Understanding cohesive zone behaviour of blast furnace based on computed tomography flow modelling in a fused bed of ferrous and coke particles
Subhasish Mitra, Mohammad Mainul Hoque, Damien O’dea, Tom Honeyands
Abstract
Performance of ironmaking blast furnace systems critically depends on the permeability of the cohesive zone which involves flow of reducing gas through a packed bed of fused ferrous and coke particles at high temperature. This study systematically investigated the effect of operating temperature on bed permeability for two different ferrous burdens - pellets, and pellets-sinter mixture supported on coke particles. To quantify the structural changes in the bed, interrupted tests at various temperatures were conducted and bed porosity was estimated using synchrotron X-ray computed tomography (CT) technique. Bed porosity showed decreasing trends with increasing temperature. A CT image based computational flow dynamics (CFD) model was developed which showed linearly decreasing trends of bed permeability parameter with increasing temperature indicating a significant loss of bed permeability in the high temperature cases. This behaviour was more pronounced for the pure pellet case compared to the mixed burden case.