Study On The Hydrodynamics Behavior Of Spout-fluid Bed With A Draft Tube

A 182mm diameter cylindrical spout-fluid bed with a draft tube using urea particles of the same size or different size as the bed material have been used to study hydrodynamics behavior of spout-fluid bed. According to change spouting gas velocity and fluidizing gas velocity, pressure drop and standard deviation of pressure fluctuation in the fluid bed were studied ,through which the minimum spouting velocity , and the spouting velocity when the solids circulation reaching one extremum were measured. The effects of the diameter of spout nozzle, fluidizing gas velocity, the height of draft tube above distributor plate, the length of draft tube and bed height on minimum spouting velocity, the minimum spouting gas quantity, the solids circulation and the rate of different size particle's circulation time have been investigated. Based on the gas-solid movement theory and experimental results, the two-valve controlling model was proposed to simulate solids circulation. It gave satisfactory agreement with those data measured in experiments.