Study On The Micromixing Characteristics In A Continuous Rotor-Stator Mixer

Many single-phase chemical reactions are sufficiently fast that the rate of mixing of the initially separate reagents influences the distribution of reaction products. This effect on selectivity disappears when the rate of energy dissipation is increased sufficiently, but in conventional stirred tank reactors, the local energy dissipation is too low to eliminate the effect. In view of conversion and selectivity are significantly influenced by micromixing, in order to improve the product properties and acquire the maximal benefit, it is necessary to find suitable reactors to fit these industrial processes. So, it is very necessary and important to explore the micromixing performance of chemical reactors.Having the characteristics of super velocity and high shear rate, though the continuous rotor-stator mixer was widely used in some complex production processes such as disperse, dissolve, emulsification and fast chemical reactions, the foundation knowledges in design and performance prediction were lackness.In this study, by using the iodide-iodate parallel-competing reaction system, micromixing efficiency in the YSTRAL CONTI-TDS-3continuous rotor stator mixer was characterized. The effects of feed time, rotor speed, reactant concentration and stator structures on micromixing efficiency or segregation index XS were investigated. The results show that the segregation index increases with the increase of rotor speed in the range of1200to1800r·min-1. The segregation index decreases with the increase of rotor speed as the rotor speed exceeded1800r·min-1. The segregation index could reach down as low as0.047which is much smaller than the corresponding value that gained in stirred tank reactors. At the same circulation degree, stator1has the best micromixing performance, when there is no stator was used, the micromixing performance is the most poor. On the base of the experimental study, through incorporation model, micromixing time is approximately evaluated to be in the range of10-3～10-4s. In view of significant fluid bypassing of the region of high turbulence intensity in single stage toothed rotor-stator mixer, micromixing efficiency in the FLUKO FDX-3triple stage toothed rotor-stator mixer was characterized.The results are of importance to the optimum design of continuous rotor-stator mixers.