Modeling Chemical Reactors from First Principles: The Batch Photocatalytic Reactor

In the modeling of isothermal chemical reactors, the specialization of the species continuity equation (for a given reactor domain) is one of the key aspects that the modeler needs to handleaddress. A helpful guidance starting point is the identification of proper simplifying assumptions for the various phenomena involved in the reaction process; these may be related to the type of reactor used, the type of reactant mixture present in the system, and the chemical reactions that taketaking place, among other aspects. In addition, for the case of a photocatalytic reactor, the modeling of the light radiation field must be coupled with the species continuity equation. The reason behind this need is based upon the dependence that of the reaction rate has withon the radiation field intensity. This field can be modelled on the basis of the photon balance equation. In this contribution, we will outline a systematic approach to derive the up-scaled equations for a batch photocatalytic reactor with degradation taking place at the photocatalytic thin film surfaces located at the wall of the reactor. Both, the species continuity equation and the photon conservation equation will be upscaled using a volumetric averaging approach in order to derive the engineering reactor equations. Furthermore, the model solution will be illustrated with conversion results of a biomedical contaminant, i.e., acetaminophen, and comparison with experimental results. Suggestions for future work will be also highlighted