Radiative heat transfer and catalyst performance in a large-scale continuous flow photoreactor for hydrogen production

In this paper, a photocatalytic water-splitting system is designed and analyzed for continuous operation at a large pilot-plant scale. Performance of the photocatalyst and reaction system is discussed, as well as photon transfer and mass transfer limitations (in the case of liquid phase reactions). The optimization of these two processes is a main objective of this study. The system uses an external power source and two electrodes immersed in the catalyst solution to supply and transfer electrons inside two reactors to replace the need for electron acceptors and donors. A nano-filtration membrane, which is utilized to separate hydrogen and oxygen in the reactor, retains the catalyst on the cathode side while allowing passage of other species to the other half cell. A Compound Parabolic Concentrator (CPC) is presented for the sunlight-driven hydrogen production system. Energy and exergy analyses and related parametric studies are performed, and the effect of various parameters are analyzed, including catalyst concentration, flow velocity, light intensity, catalyst absorptivity, and ambient temperature. (C) 2012 Elsevier Ltd. All rights reserved.