Oxygen transfer into newtonian and non‐newtonian fluids in mechanically agitated vessels

Oxygen transfer into Newtonian and non‐Newtonian fluids was studied in stirred tank vessels of 0.0018, 0.006 and 0.036 m3 operating volumes. Emphasis was given to the rheological effects of the pseudoplastic medium on the volumetric oxygen transfer coefficient, KLa. Results indicate that KLa is a strong function of gassed power input per unit volume (Pg/V) for the Newtonian fluid, but a weak function of Pg/V for the non‐Newtonian fluid, and a strong function of superficial gas velocity (Vs) for both fluids for paddle‐type impellers. KLa is found to decrease rapidly with an increase in apparent viscosity for values of μa greater than 2.0 Pa · s. In addition to various correlations, a dimen‐sionless correlation including the impeller Reynolds number, impeller Weber number, and the aeration number is presented for the prediction of KLa in a gas‐liquid non‐Newtonian system.