The flow characteristics of a 600 mm×6000 mm pressurized internal airloopreactor was studied. During the experiment the liquid superficial velocity in the draught tube was fixed at 0.008 m·s-1

gas superficial velocity ranged from 0.02 m·s-1 to 0.12 m·s-1

pressure of the reactor varied from 0 to 2.0 MPa.Local gas holdup in the draught tube and annual space was measured and correlations for these parameters were obtained.Meanwhile

the model of liquid circulation velocity on the basis of the energy balance analysis in the reactor was derived.Reasonable agreement was found between the calculated and measured data.From the model and experiment data

it was easily found that liquid circulation velocity increased with increasing gas superficial velocity and system pressure

however when gas superficial velocity and system pressure exceeded respective critical values

liquid circulation velocity increased only gently.