Oxygen mass transfer in bubble columns working at large gas and liquid flow rates

Abstract

AbstractOne of the most persistent obstacles in the study of oxygen mass transfer in bubble columns is the technical difficulty of using large liquid and gas flow rates economically. This experimental limitation is reflected in the present, very incomplete, understanding of the mass transfer characteristics of these two‐phase systems. In this work, a new experimental technique has been developed and used.The use of computer‐calculated concentration contour diagrams permitted a detailed study of the mass transfer characteristics of the zone near the distributor. No similar study has been reported in the literature until now. The ability of the axial dispersion and two‐zone models to describe the experimental data is analyzed.Finally, liquid side volumetric mass transfer coefficients have been calculated for both models. The results indicate that KLa increases, often linearly, with the superficial gas velocity. Furthermore, for the liquid‐phase range [0, 10] cm/s, KLa had a minimum at Vl ∼ 7.5 cm/s. For larger liquid superficial velocities, an increase in KLa was found. These observations were valid for the axial dispersion (ADM), plug flow (PFM) and two‐zone (T‐ZM) models.