Establishing photon absorption fields in a Photo-CREC Water II Reactor using a CREC-spectroradiometric probe

The scattering mode and the appropriate boundary conditions in a Photo-CREC Water II annular reactor are assessed from experimental data. These data are obtained by using a novel spectroradiometric probe (CREC-SP). This probe is designed to measure irradiation at different radial positions within the concentric channel. Radiation data obtained is analyzed using a calculated Monte Carlo radiation field inside the slurry photoreactor. The effect of the phase function and the boundary conditions, as relevant to the photoreactor walls, are determined. The MC method proposed by Valades-Pelayo et al. (2014, Chem. Eng. Sci., 107, 123-136) is modified in the present study to account for refraction, absorption and reflection at the probe surface. Lamp emission, refraction and reemission as well as wavelength-dependent absorption and scattering are accounted for. Regarding Degussa P25, a Henyey-Greenstein phase function with g=0.68 +/- 0.03 is needed. On this basis, a 3D LVRPA field is established. This approach also allows one to independently set boundary conditions, breaking, in this manner, their correlation with scattering parameters. As a result, this study establishes scattering phase functions and radiation absorption fields with improved accuracy. Clarification of these matters is of crucial importance for the design and scale-up of photocatalytic reactors. (C) 2014 Elsevier Ltd. All rights reserved.