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 mi2 mR-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, kLSaLS, increases from 0.02 to 0.22 mL3 mR-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 kLS 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 × 105 <Re <7 × 105. In this range, the transition of laminar flow to turbulent flow takes place, resulting in a change of the mass transfer mechanism.