Abstract
The gas–liquid mass transfer coefficient at extraordinarily large gas flow rates was investigated for a pitched bladed paddle creating upward flow in comparison with those of the Rushton disc turbine and the Scaba SRGT impeller, which are commonly recommended for gas–liquid mixing. The results indicated that the pitched bladed paddle up-pumping gave the enhanced mass transfer coefficient kLa at large gas flow rates compared to Rushton disc turbine and Scaba SRGT. In this study, it was confirmed that the kLa of DT and SRGT depend only on the aerated energy dissipation rate (εT)g at the gas flow rates of 4.8–15.8 vvm. In contrast, the kLa of PPU was shown to be functions of both (εT)g and supercritical gas velocity vs until 22.2 vvm.
