Volumetric Mass Transfer Coefficient of Oxygen in An Internal Loop Airlift Reactor with a Convergence-Divergence Draft Tube

Abstract

Experimental measurements of hydrodynamics and the volumetric mass transfer coefficient of oxygen (VMTCO) in an internal loop airlift reactor with different types of draft tubes are reported for the two-phase systems, air/water and air/carboxyl methyl cellulose (CMC) solution, and a three-phase system, air/water/resin particle, respectively. The properties of convergence-divergence draft tubes with three different structural parameters are compared with those of the conventional column draft tube. The results indicate that gas holdups in convergence-divergence draft tubes are higher than those in conventional draft tubes, the volumetric mass transfer coefficient of oxygen increases with increasing superficial air flow rates. The convergence-divergence draft tubes all show higher mass transfer capacity than the traditional ones. A 10% higher mass transfer coefficient is observed for the three structural parameters. In the air/CMC system, the volumetric mass transfer 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 the operating conditions and structural parameters is established.