THE EFFECT OF PRESSURE ON THE PHASE-TRANSITION FROM BUBBLING TO TURBULENT FLUIDIZATION

Bubbling, turbulent and fast fluidized beds are the major phases of gas-solid dense suspensions. In this paper the effect of pressure on the phase transition from bubbling to turbulent fluidization was investigated over the pressure range 0.1-0.7 MPa with a small-scale circulating fluidized bed placed in a pressure vessel. It has been found that the gas velocity at which the transition takes place decreases with increasing pressure but the solid mass flux at the transition remains almost constant. Detailed measurements on the meso-scale flow structures were made to explain the transition characteristics.