CFD and radiation field modeling of the NETmix milli-photocatalytic reactor for n-decane oxidation at gas phase: Effect of LEDs number and arrangement

Abstract

This work describes the modeling of the NETmix milli-photocatalytic reactor for n-decane oxidation at gas phase coupling non-sequential ray tracing with computational fluid dynamics (CFD). The walls of the NETmix network, comprising cylindrical chambers interconnected by prismatic channels, were coated with a thin-film of TiO2-P25. The reactor was sealed with a UVA transparent borosilicate glass slab (reactor window). The illumination system, located above the reactor window, consists of a LED plate. A total of 28 variations in the illumination system were analyzed, considering 5, 12, 18 or 30 high power UVA LEDs arranged in a staggered configuration or of 6, 15 or 28 inline LEDs. The distance between the LEDs and the reactor window was varied between 6 mm and 48 mm. The radiation field over the catalyst surface provided by each illumination system was obtained through ray tracing simulations. The registered irradiance levels, light absorption efficiency, homogeneity of the field and overall photonic efficiency were analyzed for all the 28 simulated cases. The irradiance levels registered varied between 57 W/m2 and 589 W/m2, with a light absorption efficiency up to 44%. The impact of the illumination systems on n-decane oxidation was evaluated through CFD simulations. Results allowed to appoint an ideal LEDs-to-reactor distance, that balances the irradiation levels with the radiation field uniformity, as well as an ideal system able to achieve high pollutant degradation with low power demand.