Volumetric mass transfer coefficient of oxygen in an internal loop airliftreactor with a convergence-divergence draft tube

Experimental measurements of hydrodynamics and the volumetric mass transfer coefficient of oxygen (VMTCO) in an internal loop airlift reactor with dif ferent types of draft tubes are reported for the two-phase systems, air/wat er and air/carboxyl methyl cellulose (CMC) solution, and a three-phase syst em, air/water/resin particle, respectively. The properties of convergence-d ivergence draft tubes with three different structural parameters are compar ed with those of the conventional column draft tube. The results indicate t hat gas holdups in convergence-divergence draft tubes are higher than those in conventional draft tubes, the volumetric mass transfer coefficient of o xygen increases with increasing superficial air flow rates. The convergence -divergence draft tubes all show higher mass transfer capacity than the tra ditional ones. A 10% higher mass transfer coefficient is observed for the t hree structural parameters. In the air/CMC system, the volumetric mass tran sfer coefficient of oxygen decreases with increasing bulk viscosity, while in the three-phase system VMTCO increases with the resin particle loading. The correlation equation of the volumetric mass transfer coefficient with t he operating conditions and structural parameters is established.