Investigation of the effects of various parameters on mixing time in pilot stirred tank equipped single and dual rushton impeller

The optimum positions for the additive injection and probe location in a dual-Rushton stirred tank have been investigated using Response Surface Methodology. Therefore, by keeping these two parameters (probe location and additive injection point) fixed during consequent experiments, the single Rushton impeller has been compared with a dual Rushton impeller stirred tank. The results have shown that the mixing time for single impeller systems, is lower than that for double impeller systems, so to obtain a lower mixing time in multi impeller systems, it is necessary to obtain the relation between the height of the liquid and the number of impellers. In the next part, the obtained mixing time is compared against simulation results and published data based on experimental works for a Rushton impeller in different configurations of a vessel. Also in this work the effects of superficial gas velocity and impeller rotational speed for both systems have been investigated.