Development of FCG Dynamic Control Technique at Mixed Charging of Massive Coke into Ore Layer

A controlling method of the radial mixed coke ratio distribution under high coke mixed charging, which is called FCG (Flow Control Gate) dynamic control method was studied with the aim of stable operation with high productivity and low RAR at Chiba No. 6 blast furnace. For this purpose, scale model experiments and mathematical burden distribution model calculations were performed. The effects of FCG dynamic control with ore and coke simultaneous discharging from the respective top bunkers on the mixed coke ratio distribution were examined and applied to Chiba No. 6 blast furnace. After application of FCG dynamic control, improvements of gas utilization efficiency: +0.2%, gas permeability at cohesive zone (the part of lower shaft): -14.7% and coke ratio: -4.2 kg/t (with constant RAR) were confirmed. Since June 2007, high productivity operation with low RAR has been conducted at Chiba No. 6 blast furnace.