Region-dependent oxygen transfer rate in the rectangular airlift reactor

Gas hold-up and the oxygen transfer in the zones of the internal loop airlift reactor with rectangular cross-section was studied. It was found, that the downcomer to the riser gas hold-up ratio depends on the gas flow rate, the physicochemical properties of the system and on the reactor height. The ratio of the downcomer mass transfer coefficient to the global mass transfer coefficient was less than 6%. The ratio of the downcomer to the global mass transfer coefficient slightly increased with increase of the gas flow rate and decreased with increase of the liquid viscosity. The proposed correlation for the global overall mass transfer coefficient predicts the experimental data well within 16.6% deviation. It was confirmed that the reactor height is the important parameter for a design and a scale-up of the airlift reactors.