Eight-lamp externally irradiated bench-scale photocatalytic reactor: Scale-up and performance prediction P.J. Valadés-Pelayo a , F. Guayaquil Sosa a , B. Serrano b , H. de Lasa a,⇑ a Faculty of Engineering Science, Chemical Reactor Engineering Centre, Western University, London, Ontario N6A 5B9, Canada b Facultad de Ciencias Químicas, Programa de Ingeniería Química, Universidad Autónoma de Zacatecas, Mexico highlights  A scale up methodology for photocatalytic reactors is established.  Oxalic acid degradation is carried out at different photocatalyst concentrations.  Residence time distributions are determined by using glucose as a tracer.  An efficiency factor is calculated including mixing and charge/ recombination.  Various photocatalyst concentrations and lamp emissions are used for model validation. graphical abstract article info Article history: Available online 16 March 2015 Keywords: Photocatalysis Radiation field Scale up Kinetic model Charge-recombination LVREA abstract The present study considers a scale-up methodology for photocatalytic slurry reactors. The Photo-CREC Water units used include: (a) a 2.65 L internally irradiated annular photoreactor, (b) a 9.8 L externally irradiated scaled-up unit. The LVREA (Local Volumetric Rate of Energy Adsorption Field) calculations for the bench-scale and the scaled-up reactors at different operation conditions are determined by using approaches established by Valades-Pelayo et al. [40] and Valades-Pelayo et al. [41]. In the bench-scale photoreactor, degradations of oxalic acid are carried out at different photocatalyst concentrations and lamp emissions. Residence time distributions are determined for both the Photo-CREC Water II and the Photo-CREC Water III by using glucose as a tracer. An efficiency factor is calculated in both cases including mixing mechanisms and charge/recombination phenomena using a simplified kinetic model. To avoid cross-correlation issues, all relevant parameters are determined by independent experiments. Model val- idation is also accomplished by comparing model predictions to experimental degradation rates at differ- ent photocatalyst concentrations in the larger Photo-CREC Water III. The proposed methodology confirms the applicability of reaction engineering principles for scale-up, from bench to pilot-plant photoreactors. Ó 2015 Elsevier B.V. All rights reserved. 1. Introduction Heterogeneous photocatalysis has been around for several decades [14]. The interest in this promising technology is steadily increasing [1]. This increasing interest is the result of the diverse advantages of photocatalytic technologies such as the versatility of the photocatalytic process itself; given that it can be used to degrade a wide variety of high stability pollutants [8] or produce high energy molecules [13]. Nevertheless, for photocatalytic technologies to achieve their full potential, several issues still need to be addressed [17]. One http://dx.doi.org/10.1016/j.cej.2015.03.039 1385-8947/Ó 2015 Elsevier B.V. All rights reserved. ⇑ Corresponding author. Tel.: +1 519 661 2144; fax: +1 519 6613498. E-mail address: hdelasa@eng.uwo.ca (H. de Lasa). Chemical Engineering Journal 282 (2015) 142–151 Contents lists available at ScienceDirect Chemical Engineering Journal journal homepage: www.elsevier.com/locate/cej