Low Coke Rate Operation of Blast Furnace by Controlling Size of Coke Mixed Into Ore Layer

摘要

In Kobe Steel, the blast furnace operation with low coke rate by coal injection has been carried out in order to reduce coke consumption. The problem of the operation is the increase of furnace pressure drop. The lump coke plays an irreplaceable role on keeping gas permeability in furnace. The present paper focused on two separate roles of coke as a reducing agent and as a bed spacer, and found that controlling the size of mixed coke in ore layer enabled the nut coke to be mainly consumed to regenerate CO gas, while the lump coke to form less degraded permeable bed. As a result of application to Kakogawa No.3 blast furnace, the permeability in furnace was improved and the coke rate was reduced.