Gas–powder flow and powder accumulation in a packed bed: I. Experimental study

Gas–powder flow in a slot type packed bed is experimentally studied in order to understand the flow and accumulation behaviour of powder in systems like an ironmaking blast furnace (BF). A variety of variables including gas flow rate, powder flow rate and packing properties are considered. It is found that a clear and stable accumulation region, in which the voids among packed particles are fully filled with powder, can form in the low gas–powder velocity zone at the bottom of the bed. The accumulation region is stable and shows strong hysteresis. The distribution of softening-melting layers in the blast furnace known as the cohesive zone (CZ) is modelled by inserting solid blocks into the bed. The results indicate that the inverse-V cohesive zone shape leads to low powder accumulation within the CZ and at the corner of the bed.