Application of gas-inducing reactor to obtain high oxygen dissolution in aeration process

Abstract

The application of gas-inducing reactor to obtain high oxygen dissolution has been investigated at various operation conditions including agitation speed, temperature (20–40°C), pressure (1.0–1.2 atm) and working liquid levels. Correlations regarding onset speed, agitation power consumption, gas holdup and oxygen mass transfer coefficient were established from experimental data. Onset speed can be accurately predicted with modified Froude number. The agitation power consumptions before and after onset speed is a function of Froude number and working liquid level. Gas holdup is an important factor influencing the mass transfer of oxygen after onset speed. In the study of mass transfer of oxygen ( T=20°C, P=1 atm), the highest dissolved oxygen concentration is as high as 39.34–39.92 mg L −1. The value of k L a is within 0.511–1.792 min −1. The k L a is not affected by the oxygen gas pressure (1.0–1.2 atm). However, k L a increases with increasing temperature. The gas-inducing reactor of this study has higher k L a than the other type of gas-inducing reactor under the same unit volume power consumption. The pure oxygen utilization rate of this system can be as high as 100%.