Modeling and experimental verification for photodegradation in a spinning disk reactor

The spinning disk reactor has been regarded as a process intensification device in photochemical processes, which decreases the light path length by the thin film formation created by centrifugal force. A reliable reactor model was indispensable for the practical application of photoreactors. Our previous studies proposed a spinning disk reactor with elliptic-cylindrical and cylindrical spoilers for photochemical process intensification, and then hydrodynamic parameters of liquid film thickness, photon absorption rate, and residence time distribution were obtained. Based on the obtained parameters, herein, a reactor model was further established for the description of photodegradation reaction in the innovative spinning disk reactor. Different non-ideal flow models were employed during the model development, including the tanks-in-series model and axial dispersion model. The apparent reaction rate constant of a spinning disk reactor with spoilers was determined by the photon absorption rate, which was in the range of 0.088–0.268 s−1. The reactor model was verified by the experiments on photodegradation of Methylene Blue under different disk configurations and operating conditions. The degradation efficiency of Methylene Blue could reach up to 89.8 % in 25 min at N = 200 r/min, Q = 60 L/h, and I0 = 8 mW/cm2. The deviation between predicted and experimental Methylene Blue degradation efficiencies was within ± 20 %, confirming the rationality of the reactor model. The developed model lays the foundation for the scaling-up and commercial applications of the novel spinning disk reactors.