Investigation of Surfactant Effect on the Operational Characteristics of a Packed Bed Internal Loop Airlift Reactor

Investigation of turbulency on the rate of induced liquid circulation, gas hold-up, mixing time and overall gas–liquid volumetric oxygen mass transfer coefficient. The various types of surfactants (containing Brij58, TritonX-405, Tween40, HCTBr) with various concentrations of 1-5 ppm were examined on the operational characteristics of the reactor. In surfactant solutions (in comparison with pure water), surface tension of the liquid bulk decreased and smaller bubbles were produced. Therefore, surfactants existence increases gas holdup and mixing time although it decreased the liquid circulation velocity and the rate of oxygen mass transfer. HCTBr which is a cationic surfactant was the most effective surfactant. Packing installation increased mass transfer by increasing flow turbulency and Reynolds number. Further, gas hold-up increased and liquid velocity decreased when gas bubbles movement increased. In the packed bed system, homogenous flow regime was highly observed while in the unpacked bed system the transition flow regime overcame at the high superficial gas velocities.