Cold-model numerical study of raceway shape and size effect on gas and fines flow behaviour in packed bed between the raceway and cohesive zone

ABSTRACT Operational stability and productivity of an iron-making blast furnace relies on the permeability of the bed, which is adversely affected by the accumulation of unburnt coal and fine coke powder resulting from Pulverised Coal Injection (PCI) and coke degradation. Stable operation at a high PCI rate necessitates an understanding of gas-fine powder distribution, which is affected by the cohesive zone, and raceway shape and size. A computational study of a laterally injected gas-fine powder flow through a tuyere, into a packed bed is conducted in the presence of raceway and cohesive layers. An experimental correlation is used to predict the static holdup. The effect of operational parameters such as gas flow rate, particle and fine properties, and structural parameters such as cohesive zone configuration, porosity, and tuyere protrusion are analysed. Sensitivity analysis shows raceway shape, size, and interaction with the cohesive blocks affects the distribution and accumulation of fine powder.