Estimation of Gas Holdup Using the Gassed to Ungassed Power Ratio of an Oxygen-Water System in a Stirred and Sparged Tank Contactor.

Gas holdup (εg ) and power correlations in gas-liquid (G-L) systems, apart from the physicochemical properties of the liquid phase, are dependent on impeller-sparger-vessel geometry. To date, reported correlations do not specifically address this issue, and it must be investigated with a unified approach. Here, we propose a correlation via the use of a normalized εg that involves the impeller-sparger system geometry for a vessel of standard geometry expressed as a function of an easily measurable and independent operational parameter, that is, (1 - P g / P l ), where P g / P l is the gassed to ungassed power ratio. Furthermore, our work demonstrates that P g / P l can be used as a tool for the identification of hydrodynamic regimes. Radial and axial impellers with ring spargers were used in a stirred and sparged contactor (SSTC) of 0.25 m diameter containing 1 × 10-2 m3 water. The oxygen flowrate ( Q g ) was varied from 2.5 to 40 LPM or (4.17 to 66.7) × 10-5 m3 s-1 , and the agitation intensity ( N 0 ) was varied from 1.67 to 50 rps at the temperature (θ) = 313 K under atmospheric pressure. This novel correlation is easy to use, offers reasonable precision, and can serve as a valuable alternative to more complex correlation models.