Effect of internal on phase holdups of a three-phase fluidized bed

Individual phase holdups are important dynamic parameters in the designing of three-phase fluidized bed systems. The system chosen for the present study is nitrogen as gaseous phase, an electrolyte as liquid phase and glass balls as solid phase. The gas holdup was obtained from pressure drop measurements. The obstruction area of flow path was calculated by considering all the geometric parameters of the composite promoter for evaluating the actual velocity of the fluids through the test section. It is found that the presence of composite promoter has not shown any effect on pressure drop in three-phase fluidized beds. The bed porosity data fitted well with Richardson–Zaki equation with an exponent of 2.53. The infinite dilution velocities were increased significantly because of the presence of promoter. The data on gas holdup, liquid holdup and bed porosity were in good agreement with correlations reported earlier [S.D. Kim, C.G.J. Baker, M.A. Bergougnou, Phase holdup characteristics of three phase fluidized beds, Can. J. Chem. Eng. 53 (1975) 134–139; P. Dakshinamurthy, V. Subrahmanyam, K. Veerabhadra Rao, Indian Chem. Eng. 16 (1974) 3; W.Y. Soung, Bed expansion in three-phase fluidization, Ind. Eng. Chem. Proc. Des. Dev. 17 (1978) 33; S.R. Bloxom, J.M. Costa, J. Herranz, G.L. MacWilliam, S.R. Roth, Determination and correlation of hydrodynamic variables in three-phase fluidized bed, ORNL/MIT-219, Oak Ridge National Lab. (1975)].