Inter-particle Percolation Segregation during Burden Descent in the Blast Furnace

Abstract

Inter-particle percolation at the interfaces between burden layers directly influences the permeability of the burden in the shaft of the blast furnace. This paper studies inter-particle percolation of small particles (pellets) into large particles (coke) during the burden descent through small-scale experiments and simulations. A special device was designed for making it possible to consider the effect of the increase in cross-sectional area along with the burden descent. The simulations, which are based on the discrete element method, were first validated using one experimental case. An overall agreement was found between the experiments and the simulations. The velocity distribution of coke and pellet particles in the small bed, the trajectories along the height of the bed and the quantity of percolating particles at different heights of bed were investigated. The results show a considerable inter-particle percolation of pellets into the underlying coke layer at the wall area, but also a percolation over the whole radius of the system. These findings stress the importance of taking measures to prevent percolation by proper design of the charging programs in the operation of the blast furnace.KEY WORDS: discrete element method; particle percolation; burden descent; blast furnace; packed bed.

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

“…1), which shows that the simulation has been able to reproduce the main features. 17) Thus, the DEM simulations can be considered to be in general agreement with the experimental results. Thus, DEM modeling can be used to investigate the inter-particle percolation in burden descent, although the non-spherical coke particles are represented by spherical ones in the simulations.…”

“…The experimental results 17) for a single coke or pellet layer revealed that with the expansion of the device, the left side of the burden surface declined and finally the surface of practically the whole bed showed an angle. For the coke, the declination of the surface profile was more pronounced while it was more regular for pellets.…”

“…The overall behavior was described well by the DEM simulations with spherical particles (cf. Figure 3 illustrates experimental results (left) and corresponding DEM simulation (right) for a setup where a layer of pellets was placed on a layer of coke 17) where the panels correspond to different expansions of the device, starting (at the top) with no (0 mm) and ending (at the bottom) with maximum (200 mm) expansion. The extent of inter-particle percolation grows with the expansion of the device, in particular after the 150 mm expansion stage (fourth subfigure from top) has Rate of expansion of device, w (mm/s) 1.5 been reached.…”

DEM Study of Solid Flow in COREX Shaft Furnace with Areal Gas Distribution Beams

“…In addition, the particle i bears two kinds of torque which are tangential torque T ij and rolling friction torque M ij . [39][40][41] All the forces and torques used in the model are listed in Table 1.…”

“…Table 2 lists the parameters used in the simulation. 33,41,42) The mass ratios and densities of different burdens are obtained from the plant operation in Baosteel. Table 1.…”