Fluid dynamic behaviour of two- and three-phase airlift reactors

This work deals with two- and three-phase airlift systems, employing ambient air, tap water and plastic spheres. The dependency of the main parameters (gas and liquid hold-ups, liquid circulation rate) on the only external factor, the gas flow rate was investigated. Liquid circulation rate was correlated by a pressure balance which lead to the experimental determination of an overall friction coefficient. A digital camera was used was used, in the second part of the investigation, to determine bubble hold-up and bubble size distribution. Gas flow rate in the downcomer could be inferred and a tentative correlation with the flow condition prevailing in the riser was suggested.