Influence of Solid Particles Presence on Mass Transfer Coefficient in Slurry Stirred Tank Reactor

An investigation on oxygen mass transfer in a lab-scale multi-impeller stirred tank reactor is reported. An analysis of the main factors influencing oxygen mass transfer in stirred tank has been carried out using full factorial. The factors investigated were: agitation velocity (rpm); aeration rate (vvm) and solid hold-up. The ANOVA (analysis of variance) showed the importance of the investigated factors on the oxygen mass transfer coefficient. An empirical model with operational parameters has been proposed in order to predict the oxygen mass transfer in several experimental conditions. An investigation has also been performed on the oxygen mass transfer in a lab-scale reactor, considering agitation velocity, aeration rate and solid hold-up as factors have been estimated. The solid particles presence caused a 10% for slurry 5% and 15% for slurry 10% reduction in KLa. The relationships proposed have been obtained in a wide range of experimental conditions, and they can be used both to determine if oxygen limiting conditions occur during bioleaching tests in a lab-scale stirred reactor, and, in the phase of translation of experimental data to a bigger scale. This model can use for prediction oxygen mass transfer limiting in the bioleaching uranium. The results obtained in this work emphasize the importance of incorporating the effects of physical gas-liquid-solid interactions in the design of mechanically-agitated three-phase slurry reactors.

کلیدواژه ها:

Mass Transfer Coefficient ، Three-Phase Reactor ، Stirred Tank ، ANOVA ، Solid Hold-up