Gas Permeability in Cohesive Zone in the Ironmaking Blast Furnace

摘要

Reduction of CO_2 emissions in blast furnaces is an important problem for the steel industry. Operating a blast furnace at lower CO_2 levels requires a reduction in the amount of coke that is used to maintain gas permeability in the cohesive zone. Therefore, gas permeability in the iron-ore layer of the cohesive zone should be improved. In this study, gas permeability through a packed bed with liquid was measured using an experimental sponge ball packed bed as a model. The pressure drop of the sponge ball packed bed without liquid was proportional to the square of gas flow velocity. Furthermore, it was affected by the shrinkage ratio of particles. The pressure drop of the deformed packed bed with liquid was mostly affected by liquid that overflowed from the sponge balls into vacancies in the packed bed during the deformation process. This setup can simulate the phenomenon of rising pressure drop within sinter ore at the cohesive zone. The effect of sponge ball arrangement was tested using sponge balls filled with much liquid and sponge balls with smaller amount of liquid. These sponge balls simulate gas permeability of the ore layer containing acid pellets and sintered ore in the cohesive zone. The results indicate that both the mixed arrangement and longitudinal arrangements are effective in maintaining higher gas permeability.