Modelling and design of microchannel reactor for photocatalysis

Abstract

Chemical reactions in a microreactor can offer new possibilities for many chemical engineering application fields and have been employed in photocatalysis studies. The purpose of this work is to investigate the photocatalytic degradation of salicylic acid (SA) as a pollutant model, in a continuous flow microchannel reactor in order to evaluate the influence of radial concentration profile on the photocatalytic efficiency. The study has been developed on both experimental and theoretical aspects. Microreactors have been manufactured by stereolithography in epoxy resin (Accura® SI 30) and are composed of a channel with a rectangular cross-section of about 1 mm2 with different aspect ratios defined as width/depth. Photocatalytic experiments have been performed at different flow rates. Results can be predicted by the Langmuir-Hinshelwood (LH) kinetic model coupled with surface diffusion. Computational fluid dynamics (CFD-Comsol Multiphysics) can model phenomena and confirmed the reliability of our experimental results with diffusion limitation at low flow rate.