Liquid-gas-solid mixing in stirred vessels

V.M. Barabash, N.N. Smirnov, V.-E. Zielenski

Abstract

The units with machine mixing devices are often used for processes carrying out in three-phase systems. The results of our experimental studies and analysis of literature have allowed to suggest the most expediential construction scheme of stirred vessel with new improved construction of the gas sparger ring. Processes carrying out in these units require the conditions at which the solid particles and gas are distributed in the working volume. It should be noted that these conditions differ from the similar ones in the two-phase systems, that fact can be explained by the mutual phase influence. The theoretical analysis features of interaction between bubbles and solid particles is the base for estimating the distribution of gas phase and gas hold-up in slurry. For determination of solid particles suspending conditions at the three-phase system mixing the pulsation and probabilistic lifting mechanism is taken. This mechanism suggests that the particles transfer in the vertical direction take place because of pressure pulsation caused by pulsation of the longitudinal component of velocity. Taking account of this information it is possible to calculate the mass transfer coefficient in the processes dissolving of solid particle at three-phase mixing. The comparison of the theoretical analysis results with the numerous experimental data allows to use the offered model in the engineering rating practice.