Mass-Transfer Characteristics of Large Paddle Impeller in Surface Aeration with Liquid Level Change

摘要

The aim of this study is to investigate the mass-transfer characteristics of surface aeration with liquid level change. The mass-transfer of conventional multi-stage impellers are unsteady and inefficient at liquid level change, so that we have tested the unique large paddle impeller that we developed and named "Maxblend~®" in comparison with conventional impellers. As compared to the pitched blade turbine (downward) and the Rushton turbine, the large paddle impeller exhibited very interesting features, that is, a large and steady k_L a value of surface aeration without sparging can be obtained at each liquid level by large paddle impeller because of good and constant gas entrapment by strong surface renewal of liquid circulation and its continuous shape from bottom to top.