Dynamics of Burden Materials and Gas Flow in the Blast Furnace

Abstract

Descending behavior of burden materials and distribution of stresses in the blast furnace were studied by the use of a reduced-scale model.
Appearance of burden descent is, macroscopically, like a plug flow at upper part of the belly and a funnel flow at the bosh. However, at the peripheral region close to the wall, a mixed zone of are and coke is formed and its dimension depends on the shaft angle and the shape factor of burden.
Stress field is an active state in the shaft and is a passive state in the bosh. At the belly in a transitional state, the horizontal stress develops markedly.
Particles flow into the raceway passing through a narrow part above the tuyere nose. A profile of dead coke zone estimated by a theoretical consideration of the stress field of passive state shows a good agreement with the experimental results.
The gas permeability of a moving bed with a funnel flow is higher than that of fixed bed because of the increase in void fraction.