Blast furnace performance as influenced by burden distribution

Burden distribution is one of the key operating parameters influencing blast furnace performance, particularly the productivity and the coke rate. The proper distribution of burden materials improves bed permeability, wind acceptance, and efficiency of gas utilisation. In furnaces operating with high coal injection rates, the distribution resulting in predominant central working (steep cohesive zone profile) was found to be beneficial. Since a high coal injection rate increases the peripheral working (wall heat flux), an attempt should be made to minimise the wall heat flux by striking a proper balance between peripheral and central working. In a typical Indian blast furnace equipped with a bell-less (Paul Wurth) distribution system, the decrease in coke rate that is due exclusively to burden distribution was found to be 10–12 kg/thm.