Large Scale Simulation of Coke and Iron Ore Particle Motions and Air Flow in Actual Blast Furnace

Abstract

The computational program for the particle and the air flows in an actual blast furnace using Distinct Element Method (DEM) for the coke and the iron ore particles of which number was about 16 million and the Finite Difference Method of which computational cell number was about 3 million for the numerical analysis of Navier–Stokes equations with the interaction terms between the air and the particles has been developed. The motions of coke and iron ore particles and the air flow in the blast furnace have been simulated using this program. The computational domain in the tangential direction was 1/4, which was 90 degree of the region of the horizontal plane and in which 10 tuyeres were arranged, of the actual blast furnace. The simulation results showed that the model softening melting cohesive zones, which were formed by the model that 50% volume of the ore particle melted and the diameter Dp reduced to 0.794 Dp by melting the particle surface at the 1200°C line and the residue of the ore particle melted down completely at the 1400°C line, largely affected the air and the coke particle flows and caused the non-homogeneous and unstable flows. The air was divided into two flows at the softening melting cohesive zones. The one was the flow with the slope angle nearly 45° from the horizontal toward the furnace wall in the central region and the other is vertically upward flow in the region near the furnace wall. The coke and ore particle velocities on the wide region of the furnace wall became very low. These nearly quiescent solid particle layers might cause the scaffold of the solid particle bed on the furnace wall. The results also showed that the interaction between tuyeres affected the shape and the stability of the raceway and influenced the particle and the air flows in the wide region on the raceway. Hereafter we will continue to calculate the air and the particle motions, and present the various unstable motions which would bring about an extraordinary event in the actual blast furnace.