Gas holdup and axial dispersion coefficient in gas-liquid cocurrent spout-fluid beds

An experimental investigation was carried out to determine the effect of gas velocity, liquid velocity, and column diameter on the gas holdup and axial dispersion coefficients in cocurrent spout-fluid beds in three columns with diameters of 74, 114, and 144 mm, all with a height of 1.20 m, at superficial gas and liquid velocities of 0.001-0.186 m . s(-1) and 0.002-0.06 m . s(-1), respectively. The axially dispersed plug flow model equation was solved by using the finite difference technique and compared with the analytical solution proposed by Uysal and Anabtawi. Gas holdup was found to increase with increases of both the gas velocity and column diameter. The effect of liquid velocity on the gas holdup was found to be insignificant. The axial dispersion coefficient was found to increase with increasing gas velocity, liquid velocity, and column diameter. New correlations for predicting the gas holdup and axial dispersion coefficient in a spout-fluid bed and based on large data for a two-phase system are presented with maximum deviations not exceeding 6 and 7%, respectively.