In particular, consideration is given to the prediction of macro-scale phenomena of flow regimes, pressure drop in fixed and fluidised beds, minimum fluidisation velocity, dispersion and liquid solid mass transfer.
Imaging in 3D showed that the central jets were the longest for flow rates below minimum fluidisation.
Above minimum fluidisation, the outer jets, nearest the wall of the fluidised bed, arched inward towards the central axis.
The experimental variables studied included: (i) gas flow rate, varying from 2 to more than 10 times that required for minimum fluidisation; (ii) mean particle size, ranging from 0.138 to 0.275 mm; and (iii) internal bed thickness from 2.1 to 4.9 mm.
This study experimentally examines the hydrodynamics of packed and fluidised beds in terms of pressure drop, bed expansion and minimum fluidisation velocity in tube sizes with inner diameters of 0.8, 1.2 and 17.1 mm.
under bubbling fluidisation and just below minimum fluidisation.
Experimental minimum fluidisation velocity results compare well with the literature and theoretical values calculated from existing models.
At a constant gas injection rate through the orifice higher minimum fluidisation velocities result in larger bubbles and decreased leakage.
At superficial gas velocities in excess of the minimum fluidisation value, the pressure drop fluctuates regularly but not sinusoidally.
Investigations into minimum fluidisation velocity, solids flux, gas bypassing between reactors, and pressure profiles of the system have been undertaken, the results of which are presented and discussed.
