Effect of a gas-liquid separator on the hydrodynamics and circulation flowregimes in internal-loop airlift reactors

The role of the gas-liquid separator on hydrodynamic characteristics in an internal-loop airlift reactor (ALR) was investigated. Both gas holdup and l iquid velocity were measured in a 30 dm(3) airlift reactor with two differe nt head configurations: with and without an enlarged separator. A magnetic tracer method using a neutrally buoyant magnetic particle as flowfollower w as used to measure the Liquid velocity in all sections of the internal-loop airlift reactor. Average liquid circulation velocities in tire main parts of the ALR were compared for both reactor configurations. At low air flow r ates the separator had no influence on gas holdup, circulation velocity and intensity of turbulence in the downcomer and separator, At higher superfic ial air velocities, however, the separator design had a decisive effect an the hydrodynamic parameters in the downcomer and the separator, On the ethe r hand, the gas holdup in the riser was only slightly influenced by the sep arator configuration in the whole range of air flew. Circulation Wow regime s, characterising tile behaviour of bubbles in the downcomer, were identifi ed and the effect of the separator on these regimes was assessed. (C) 2001 Society of Chemical industry.