Coke Properties and Operational Conditions of Blast Furnace to Prevent Coke Degradation in the Raceway

Synopsis : Fine coke.which mainly oricinated in the raceway, has a great influence on the blast furnace operation.Generation behavior of coke fine in the raceway was investigated by the coke combustion experiments and the examination of the coke collected from Chiba No. 5 blast furnace.Fraction of fine coke in deadman increased as coke strength decreased, as coke CRI decreased, as flame temperature decreased or blast velocity increased.And influence of coke properties on coke fine generation in the raceway was confirmed from the coke combustion experiments.These results imply that coke was gasified and broke down to generate fine coke in the raceway.Mathematical model of fine coke generation in the raceway, which consists of coke gasification and destruction in the transient region and combustion in the dense oxygen region, clarified that high strength coke, high reactivity coke, high flame temperature or low blast velocity decreases in coke fine generation in the raceway.