Investigation of micro- and mesomixing in a reaction mixing pump

The present study investigates the application of a reaction mixing pump (RMP) as a reactor for mixing-sensitive reactions. In a RMP, the effect of impeller speed and feed rate ratios on the selectivity of the Villermaux-Dushman (VD) reaction system was investigated through experimental means. The observations revealed three distinct mixing regimes, namely backmixing, micromixing and mesomixing, which were dependent on the feed ratio. Increasing impeller speed led to an increase in the selectivity of desired products in the micro- and mesomixing regimes, while it had the opposite effect in the backmixing regime. In the backmixing and mesomixing regimes, selectivity was sensitive to alterations in feed ratio; conversely, in the micromixing regime, changes in feed ratio did not affect the selectivity significantly. In addition, the engulfment micromixing model was utilised to predict selectivities in the micromixing regime, demonstrating a strong correlation with the experimental data. For the first time, the W-Z-transformation was applied to the VD reaction system within the context of the engulfment model. High energy dissipation rates resulted in a reduction of the mixing times to the order of magnitude of 10 -3 s. This was accompanied by an increase in the selectivity of desired products in the micromixing regime. These observations emphasize the efficiency of RMPs as a promising class of reactors for reactions that are sensitive to mixing. • The performance of a reaction mixing pump as a reactor was investigated. • The Villermaux-Dushman reaction system was used to study selectivity. • Micromixing, mesomixing, and backmixing regimes were observed. • The engulfment model was used to describe the micromixing regime. • Short mixing times and high selectivities for desired products were observed.