Modeling and Experimental Study of Gas Phase Holdup in an Agitated Bubble Column

In this study, gas phase holdup in a gas-liquid bubble column reactor was experimentally studied. To conduct experiments, a bubble column with a height of 54 cm and a diameter of 10.4 cm was applied. The studied systems include water-air, Gasoline-air, and Behran oil-air. Experiments were carried out in the range of 400-50 rpm agitator. Based on the Buckingham π theorem, a semi-experimental model for gas phase holdup was presented. The results showed that with increasing viscosity from 0.001 to 0.0136 gas phase holdup loss due to high adhesion of bubbles at high viscosity and also the increase of bubble size at the output from the distributor decreases from 0.41 to 0.333. Among the selected systems, the gas phase holdup of the gas-air system was maximized. The results also showed that in materials with low viscosity, the gas phase reduction was due to the formation of liquid vortex movement and air canalization by the agitator. The best agitator speed to increase the gas phase holdup at water and oil are 150 and 400 rpm, respectively.