Numerical Study Using Discrete Element Method about Coke Particle Behavior in Cohesive Zone

摘要

The simulation of cohesive zone in the blast furnaces is conducted using 2-dimensional discrete element method. The simulation is divided into two parts; (1) the group simulation of the flow of coke and ore particles in the cohesive zone when the reduced ore particles start to shrink and disappear with melting, and (2) the biaxial compression test simulations of breakable single coke particle with receiving x and y directional stresses which is evaluated from the group simulation. In addition, a gasification model is developed and combined with the coke model for the biaxial compression test simulation. The gasification process is simulated by removing element particles for a fixed amount.In the group simulation, coke particles have been found to move actively not only the axial (horizontal) direction but also the radial (vertical) direction due to the elimination of ore particles in the melting zone. Due to these movements, the coke layers are severely distorted and the coke layer thickness is much decreased. The developed stresses on particles in the group simulation are recorded and this stress information is applied to a non-gasified and the gasified coke model to simulate the coke breakage behaviors. In the non-gasified case, both of the volume breakage and the surface abrasion are not observed. In the gasified case, the surface abrasion and fragmentation occur, but the volume breakage is not observed under the present simulation condition.