Aeration and Mixing in Loop Reactors Equipped With Fine Bubble Diffusers and Slow Speed Mixers: A Full Scale Study

摘要

Mixing and aeration characteristics obtained on three full scale loop reactors for 28rnconfigurations (different mixers’ location and rotation speed, air flow rates and diffuser grids’rnlocation) were analyzed. The propellers’ thrust was measured in situ. Observed values varyrnwith the tank geometry, the location of the mixers and the induced axial velocity. In situ thrustrnvalues are lower than the nominal ones obtained during shop tests, by 10 to 30 %. For thernnominal rotation speed of the propellers, observed thrust-to-power ratios are comprisedrnbetween 685 and 875 N kW~(-1). In agreement with previous results, an increase in the oxygenrntransfer rate with the axial velocity was observed, due to a partial neutralization of the spiralrnflows formed at the edge of the aerated zones. Aeration efficiency is not decreased, as thernadditional power consumption due to mixing is offset by the oxygen transfer enhancement.rnSAE values are comprised between 2.0 and 2.6 kg O2 kWh~(-1). Such on site results arernespecially important to be used as input and output data in CFD models.