The hydrodynamic characteristics, viz, the pressure drop, bed expansion and phase hold up profile of a co-current three-phase fluidized bed with an antenna-type air sparger have been determined. Correlations for minimum liquid fluidization velocity, bed voidage and gas holdup have been developed. The bed voidage is found to increase with the increase of both liquid and gas velocities. The gas holdup increases with gas Froude number. but decreases with liquid Reynolds number. The gas holdup is a strong function of the Froude number, The experimental values have been found to agree with the correlations. (c) 2008 Elsevier B.V. All rights reserved.