Charge material distribution behaviour in blast furnace charging system

Abstract

Smooth operation, permeability control and high energy efficiency are critical operational indices which relate to the overall economic measure of the blast furnace (BF) ironmaking process. The BF charging system is central to the realisation of good operational indices. However, the readiness of granular material to segregate (de-mix) due to particle geometry (size, shape, distribution and density) regardless of the material has been uniformly blended, remains a challenge. This research paper presents discrete element modelling (DEM) study to investigate, characterise and compare the effects of initial positioning of high flowability pellets material in ternary ferrous mixtures with two sinter material components of different sizes. In order to elucidate quantification of the particle-particle scale distributions of particle types relative to others as charge materials mix as well as providing useful inferences on segregation and dispersion, a quantitative approach using near-neighbour separation index (NNSI) was used to give instantaneous quantitative description of the material status in space and time during multiple handling state positions within the charging system. Based on the results obtained from the DEM simulations, the initial positioning of the high flowability pellets material in the upstream of the BF charging system has a bearing on the discharge flow characteristics in the downstream discharging operations as well as mixing and segregation behaviour of the material. The mobility of the high flowability pellets particles, compounded by their relatively small size, influence the overall material movement and interactions as they are acquiescent to percolation and sieving. The observations in this study form a significant contribution for considerations of a discharge model formulation for a mathematical model possible of tracking real-time material movements in a BF charging system.