Liquid−Solid Mass Transfer and Reaction in a Rotor−Stator Spinning Disc Reactor

The heterogeneously catalyzed oxidation of glucose is performed in a rotor−stator spinning disk reactor. One side of the rotor is coated with a Pt/C and Nafion catalytic layer, resulting in a liquid−solid interfacial area of 274 m i 2 m R −3 . At the lowest rotational disk speed, 26 rad s −1, the reaction is liquid−solid mass transfer limited; at the highest rotational disk speed, 180 rad s −1, the intrinsic kinetics are rate determining. The experimental overall reaction rates are fitted with a resistances in series model, with the activation energy, pre-exponential factor, and volumetric liquid−solid mass transfer coefficient as parameters. The volumetric liquid−solid mass transfer coefficient, k LS a LS, increases from 0.02 to 0.22 m L 3 m R −3 s −1 for a rotational disk speed of 26 to 157 rad s −1 . These values are high in comparison to conventional reactors, like packed beds, in spite of the low liquid−solid interfacial area used in this study. The values of the liquid−solid mass transfer coefficient k LS are 1 order of magnitude higher compared to values reported for packed beds. The Sherwood number for the liquid−solid mass transfer in the rotor−stator spinning disk reactor depends on the Reynolds number to the power 2 in the range 1 × 10 5 < Re < 7 × 10 5 . In this range, the transition of laminar flow to turbulent flow takes place, resulting in a change of the mass transfer mechanism.