1993 Volume 33 Issue 6 Pages 681-686
High permeability of the gas and molten materials in the dropping zone of a blast furnace is the major factor for achieving stable furnace operation with high productivity. Basic studies of the flow behaviour of liquids in a packed bed are required to grasp the effect of various operational changes on conditions in the dropping zone.
Experimental work and mathematical modelling were carried out for a liquid flow in the structured packed bed with different size particles which is frequently observed in the dropping zone in actual furnaces. Small particles were introduced into the central region, which was 0.07 m in radius and 0.2 m in height, and coarse particles were packed into the remaining area in order to reproduce the structure in the lower part of a blast furnace. The bed consists of two regions, the central region with small particles and the surrounding region with coarse particles of 6 mm in diameter. A liquid was supplied at the centre of the bed surface and radial distribution of liquid mass velocities were measured at the bottom of the bed. The size reduction of small particles shows a lower mass velocity at the centre, although the liquid profiles exhibit their maximum at the centre. Liquid dispersion in a structured packed bed was modelled by a new method, taking into account the statistical dispersion process and the effect of the physical properties of the liquid on permeability. The model was validated against measured data on the radial distribution of mass velocities and the effect of small particles diameters.