Abstract
It is known that the pulverized coal injection operation leads to increase in the ore/coke ratio in a blast furnace and some of the injected pulverized coals are accumulated in the blast furnace, being not burnt. Because these situations could make the blast furnace operation unstable, the control of gas flow in the blast furnace, which corresponds to the pulverized coal injection operation, becomes necessary.
In this paper, a systematic experiments were made to clarify the effect of ore/coke ratio on chemical reactions in a cohesive layer which dominates the gas flow in a blast furnace. The effects of ore/coke ratio and unburnt pulverized coal on the mechanical strength of coke slits in a blast furnace were also investigated by using CO2 gas with volatile matter removed char prepared from a coal.
It was found that:
(a) Reduction of ore in a cohesive layer is affected by the gas flow resistance through the cohesive layer due to the increase in thickness of ore layer.
(b) Unburnt pulverized coal is gasified more rapidly than lump coke and, hence, the degradation of coke is decreased.
