Dust Release from Aggregative Cohesive Powders Subjected to Vibration

Abstract

Dust is released from a mechanically vibrated bed of cohesive powders aerated close to the minimum for fluidization. The materials tested were silica and potato starch. The effect of both vibration intensity and vibration frequency on dust formation are verified, and a model to account for these two variables has been developed. A dimensionless dust release parameter has been defined and calculated from the experimental results. This parameter is able to explain the role of the acceleration due to vibration and of cohesive interparticle forces, also accounting for the magnification effects of acceleration intensity close to resonance conditions. However, the same parameter is unable to fully account for changes in dust emission induced by fluidized bed bubbling promoted by vibration frequencies close to resonance. Without considering these effects, frequency determines a reduction of dust release that should be explained by introducing some effects other than those considered in our model

Parametric study of the particle motion induced by a vortex shaker

“…Some tendences can potentially be accounted for. In general, the decrease in the particle velocity under some conditions might be explained by an increase of interparticle forces that can considerably reduce the particle mobility owing to the larger amounts of particles produced by desaggregation due to the test tube rotation and vibration [28].…”

Development and application of a novel cake strength tester

“…Many different inter-particle forces are responsible for the each of the caking mechanism. For instance, caking could happen due to different inter-particle forces such as liquid and solid bridges, van der Waals forces, magnetic force and electrostatic force [3]. The major adhesive force in a dry, consolidated and finegraded powder bed is the van der Waals forces [4].…”

Characteristics of Vibrating Fluidization and Transportation for Al2O3 Powder

“…These studies have investigated the flow pattern [ 20 , 24 ] and flow characteristics [ 19 , 20 , 21 , 22 , 23 , 24 ] to the particulate materials of micron- and nano-size when the vibrating amplitude, frequency, and fluidized air velocity are changed. Regarding the particle dispersion in the vibrated powder bed, there is also an experimental study of the release of dust from cohesive powder by vibrating fluidization [ 25 , 26 ]. On the other hand, there are no research reports on the transportation characteristics of powder using a vibrating fluidized bed.…”