A new numerical method to analyze reaction and heat transfer in layered packed bed of layered burden materials was developed. This method combines steady-state simulator of blast furnace operation and "digital basket" model. The digital basket is a fixed bed of burden materials through which the reducing gas flows. The fixed bed can be a mixture or layers of iron ore and coke. The mathematical expression for the digital basket is a subset of blast furnace simulator which consists of one-dimensional conservation equations of mass, heat and chemical species, and rate equations of reactions and heat exchange for gas and burden phases. The reducing gas temperature, composition and flow rate are used as the boundary condition at the bottom of the digital basked. These variables are extracted along a trajectory of descending burden material that is estimated by the blast furnace simulator. This treatment combines the blast furnace simulator and the digital basket model, and allows to reproduce the reaction and heat transfer behaviors of the burden bed descending in the blast furnace. This new method was applied to mixed and layered packed bed of iron ore and coke and successfully revealed the differences in the processes of heating and reduction reaction. The results showed that the deviations of the gas and solid compositions in the burden layer were enlarged under the mixed charging condition compared to the mixed charging. This is due to the separate occurrence of the reduction reaction and the coke gasification.
Hiroshi Nogami (Thu,) studied this question.