CHARACTERIZATION OF AXIAL NONUNIFORMITY IN FLUIDIZED BED BY THE AMPLITUDE OF LOCAL PRESSURE DROP FLUCTUATIONS

The amplitude of local pressure drop fluctuations was used to characterize the axial stability of a freely bubbling fluidized bed. The experiments were carried out in a bed of 0.318 m dia at normal and elevated temperatures. It was found that the transition between a freely bubbling zone, consisting of small bubbles distributed uniformly across the bed, and a zone of incipient slugging occurs if bubble to bed diameter ratio is about 0.15. The amplitude of local pressure drop fluctuations was found to be a linear function of gas velocity in a broad range of temperatures if measured in the freely bubbling zone