Fluidization Characteristics in Micro‐Fluidized Beds of Various Inner Diameters

Abstract The fluidization characteristics of quartz sand and fluid catalytic crack (FCC) catalyst particles in six micro‐fluidized beds with inner diameters of 4.3, 5.5, 10.5, 15.5, 20.5, and 25.5 mm were investigated. The effects of bed diameter ( D t ), static bed height ( H s ), particles and gas properties on the pressure drop and minimum fluidization velocity ( u mf ) were examined. The results show that the theoretical pressure drops of micro‐fluidized beds deviated from the experimental values under different particles and gas properties. The possible reason is due to an increase in bed voidage under smaller bed diameters. The equations for conventional fluidized beds did not fit for micro‐fluidized beds. u mf increased with decreasing D t . When the ratio of H s to D t ranged from 1:1 to 3:1, u mf was characterized by a linear equation with H s, while the slope of the equation u mf versus H s decreased with increasing D t . In this paper, D t / d p and H s / d p were defined as dimensionless variables and a new equation was developed to predict u mf in micro‐fluidized beds under the present experimental conditions.