Effect of Burden Distribution Pattern on Gas Flow in a Packed Bed
Jizhobg Chen, Tomohiro Akiyama, Jun-ichiro Yagi
Pulverized coal injection (PCI) into a blast furnace causes low permeability in the shaft zone of the blast furnace. It is therefore necessary to optimize the burden distribution which affects gas flow resistance for achieving high injection rate of pulverized coal. The main purpose of this study is to clarify the influence of the burden distribution pattern on the gas flow in a blast furnace experimentally and theoretically. A two-dimensional mathematical model for gas flow was developed based on the Ergun's equation in the packed bed and on the k-ε turbulence model in the freeboard, respectively. The gas flow phenomena in the packed bed were analyzed at different gas velocities for several conditions of the inclination angle of layer, layer number and layer thickness ratio, Lo/Lc.
As a result, the increase of Lo/Lc led to the rapid increase of pressure drop in the Lo/Lc range less than 2.0 under the condition of constant total height of the packed beds. The pressure drop decreases with the increases of the inclination angle and layer number under the fixed height of the packed beds. It could be inferred that the charging pattern of thinner layer is effective to reduce the pressure drop in a blast furnace operating with high PCI rates from the analysis of gas flow in the packed bed without interfacial resistance and fine powder.
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