Effect of Baffles on Homogenous-Heterogeneous Regime In Two Phase Bubble Column With Non-Newtonian Liquid


This work presents a comparison of the flow region in baffled and unbaffled bubble columns with Newtonian and non-Newtonian liquids. The experiments were carried out in column of 15 cm inside diameter and 2m height with aspect ratio (L/D=4.5), using perforated plate gas sparger, 54 holes of 1mm diameter, and with free area of holes to cross sectional diameter of vessel 0.24. The two phase system consists of air and non Newtonian liquid of polyacrylamide (PAA). The gas holdup was measured and the transition point from homogenous to heterogeneous region was calculated under different concentrations of PAA (0,0.01, 0.05, and 0.1)wt% in baffled and unbaffled columns. The results show that the measured values of gas holdup are increased in the presences of baffles in homogenous region, while, they decrease in heterogeneous region. The transition points of gas holdup and superficial gas velocity were estimated from drift flux plot. It was concluded that they were decreased with increasing viscosity and increased in the presence of baffles.