The Development of a Novel Photoreactor for the Photocatalytic Wet Oxidation of Organics in Radioactive Waste

摘要

This paper, a joint prize-winner at last year's UNTF meeting, describes work carried out at the Department of Chemical Engineering in Cambridge, on the development of a novel photoreactor - the Pulsed Baffled Tube Photochemical Reactor (PBTPR). The PBTPR has been proposed as a viable reactor configuration for the photocatalytic wet oxidation of organic materials in radioactive waste. The PBTPR finds special application in the treatment of waste streams containing solid particles (eg ion-exchange resins) due to the excellent solids handling capacity of pulsatile flow (Oscillatory Flow Mixing) in a baffled tube. The basic principles of photochemistry, wet oxidation and pulsatile flow, upon which the PBTPR principle lies, are described. Results are reported of current work on the photocatalytic wet oxidation of methylene blue (using TiO_2 as photocatalyst). It has been found that higher photon utilisation efficiencies can be obtained using the PBTPR as compared with a similarly scaled 'conventional' photoreactor. Reaction rates in a heterogeneous scattering medium have also been found to decrease with increasing Oscillatory Reynolds number.