Abstract
In ironmaking blast furnaces, the particle size distribution and voids in the coke bed affects the upward flow of gas, and consequently, the efficiency of the combustion reaction. To clarify the influence of coke pulverization on the packing structure of the coke bed, the permeability of the bed was evaluated using detailed dynamics simulation and geometric data analysis. To obtain detailed 3D morphology of the coke, we derived digital geometric data using rotational strength tests. Using the Euler–Lagrange coupling approach with the multisphere discrete-element method, the effect of the volume fraction of fines and distribution in the coke bed on the gas flow was analyzed. The void shape in the 3D coke bed structure was quantified using geometric data and simulated gas flow distributions. Although a continuous void network was observed in the packed bed before pulverization, areas of highly restricted (or no) gas flow were observed after pulverization. The dominant effect of coke degradation on the packed bed structure was the disruption of the gas flow path because of fines clogging the pores and narrowing the gas flow path. The developed simulation method can comprehensively analyze the effects of coke degradation on the gas flow distribution in the coke bed and can be used to analyze and control the instability of industrial blast furnaces.
