Effect of DEM Parameters on the Simulated Inter-particle Percolation of Pellets into Coke during Burden Descent in the Blast Furnace

Abstract

Inter-particle percolation at the interface between the burden layers in the blast furnace influences the permeability in the lumpy zone, and, in particular, in the cohesive zone, where the iron-bearing materials start softening to finally melt. This paper presents a simulation study of the effect of particle properties on inter-particle percolation of small particles (pellets) into a layer of larger particles (coke) during burden descent in the blast furnace. An expanding experimental device in small scale was applied to mimic the conditions at burden descent in a shaft with growing radius, and results from these experiments were used as a reference for the simulations and to validate the computational results. The simulations, which were based on the discrete element method, studied the effect of factors such as friction and restitution coefficients, shear modulus, as well as pellet diameter on the extent of percolating particles. It was found that coke shape, pellet diameter, static friction and inter-particle rolling friction and restitution had a marked effect on the percolation, while rate of expansion of the device, density of pellet and shear modulus proved to be of minor importance.