Liquid Holdup and Abnormal Flow Phenomena in Packed Beds under Conditions Simulating the Flow in the Dropping Zone of a Blast Furnace

Measurements were made of the total holdup, gas pressure drop and flooding velocities for flow through packed beds at low superficial velocities of liquid for various degrees of wetting between the liquids and solids.Correlations for both static and dynamic holdup, and a flooding diagram which is valid for non-wetting as well as wetting flow, were obtained.An instability of the bed, in which a transition from a stable to a fluidised bed occurred, was observed before the onset of flooding in some experiments. A diagram was developed to differentiate fluidisation from hooding in relation to the flow conditions. The diagram indicates that, in blast, furnaces, fluidisation of the coke bed is likely to start before the onset of flooding by the slag. The abnormal flow phenomena which could occur in the furnace are discussed in terms of the fluidisation of the coke bed in the dropping zone.