Breaking agglomerates with low-velocity gas jets in a fluidized bed

Abstract

Agglomerate formation is an issue in several industrial fluidized bed processes, such as fluidized coating, fluid coking, biomass combustion, biomass gasification, and silicon refining. Vigorous bubbling can help reduce agglomeration, but is not intense enough to break strong agglomerates. Moreover, increasing the fluidization velocity of the whole bed may have undesirable outcomes, such as increased elutriation. High-velocity gas jets will also attrit the bed particles. This paper focuses on using low-velocity (10–30 m/s) horizontal gas jets to break agglomerates in a fluidized bed. A gas jet cycles, and the shear from the emulsion solids displaced by the expanding jet cavity helps break agglomerates. Equipment configurations that provide a high fraction of broken agglomerates for a typical agglomerate will be effective for other agglomerates of various strengths. Agglomerate breakage can be enhanced by increasing the jet nozzle flowrate or the flow of gas bubbles into the jet cavity.