FLOW PATTERN IN A FLUIDIZED-BED WITH A NON-FLUIDIZED ZONE

The flow pattern of a fluidized bed with non-fluidized zones is invest igated both experimentally and theoretically. Experiments were carried out in such a way that air was introduced only through part of the di stributor. The results show a significant amount of air flowing to the zone where no air is introduced. However, once the gas velocity excee ds the minimum fluidization velocity in the zone where the air is intr oduced, the cross-flow hardly changes upon further increase of the gas velocity. A continuity equation and Ergun's equation are used to desc ribe the flow pattern and pressure distribution over the bed. Very goo d agreement between the experimental and calculated results is achieve d without any fitting parameter. The results are relevant to the under standing of heat transfer behaviour of a fluidized bed combustor (FBC) that is only partly fluidized to control its load.