HYDRODYNAMICS IN RECTANGULAR AIRLIFT REACTORS - SCALE-UP AND THE INFLUENCE OF GAS-LIQUID SEPARATOR DESIGN

Experiments were conducted on air-lift reactors with different liquid volumes, aspect ratios, and gas-liquid separator configurations, with constant downcomer to riser cross-sectional area ratio and riser/downcomer height. Reactor performance was highly dependent on the gas-liquid separator design. By changing the latter, the mode of operation could be changed from that of a concentric tube reactor (with gas recirculation) to an external loop reactor (without gas recirculation). Liquid velocity and overall gas hold-up data were correlated to the power per liquid volume and "Disengagement Ratio", a geometric parameter describing the separator's configuration. During scale-up, similar gas hold-ups and liquid velocities were found in laboratory and pilot reactors. A modified air-lift reactor with an enlarged channel for a gas-liquid separator also was studied.