Influence of Above Burden Probes in Blast Furnace on Centre Coke Charging and Subsequent Operational Stability

Formation of a good central chimney is integral to stable blast furnace operations, for which large sized coke, also known as centre coke, is charged in the centre of blast furnace. Internal visualization of the blast furnace has revealed that the above burden probes inside can alter the course of falling centre coke. This disturbs the central chimney shape and affects the gas flow inside, causing abnormalities. Above burden probes provide useful information regarding the top gas radial temperature profile and composition. They practically dictate furnace operational philosophies, hence their presence inside the furnace is non-questionable. The influence of their positions as well as other operating parameters like chute angle and charging time of centre coke on final heap formation is studied in detail using discrete element method (DEM) simulations. Rotating chute and above burden probe geometries are incorporated in the simulations and flow of model centre coke (derived from careful experimentation) is simulated. Material flow and heap formation is found to be better at steeper chute inclination angles at the cost of some scattering due to stiffeners located at chute bottom. Above burden probes in their original positions disrupt heap formation drastically, however moving them slightly outside enhances proper heap formation. Optimum ranges for chute angle and above burden probe repositioning are determined, and the effect of implementing these changes in blast furnace are discussed as well. [GRAPHICS] .