Effect of internals and sparger design on mixing behavior in sectionalized bubble column

Abstract

An experimental study has been carried out to investigate the effect of internals and sparger design on mixing time (θ_mix) and fractional gas hold-up (ε_G) in a batch mode sectionalized bubble column. Air and water were used as the gas-liquid phases, respectively. In the present work, sparger with the percent free area (% FA) of 0.136 and 0.6% has been used and the superficial gas velocity (V_G), liquid height to column diameter (H_c/D), percent free area of the sectionalizing plate was varied from 0.06 to 0.295 m s⁻¹, 3 to 4 and 4 to 23%, respectively. It was found that there is no significant effect of the sparger design on the mixing time but it does strongly depend on V_G, H_c/D and % FA of the sectionalizing plate. The one-dimensional dispersion model successfully predicts the tracer concentration profile and the longitudinal dispersion coefficient. Also, the effect of the presence of the electrolyte too has been studied by adding a known volume of the tracer solution (NaCl). Correlations have been developed for the estimation of the fractional gas hold-up, mixing time, longitudinal dispersion coefficient (D_L) and the intercell exchange velocity (u_B).