(493b) Scale-up of Co- and Counter-Current Irradiated Photochemical Reactors Using Common LEDs for Industrial Applications

Common cross-currently illuminated photochemical reactors, i.e. radially irradiated reactors, lack the energy efficiency to be competitive in industry. The use of co- and counter-current illumination was previously proven to increase reactor performance, but using a less efficient collimated LED.^1,2 By studying the use of non-collimated LEDs (illuminates the reactor along its axial axis) for the use in co- and counter-currently illuminated reactors efficiency can potentially be improved (Figure-1).

For this study, 4 types of LEDs were used ranging in total viewing angle from 20° to 120°, the reflectivity of the reactor material was varied, the absorbance (specific absorbance and path length) was altered and the tube diameter was investigated. The model results indicate that the optimal light source for achieving efficient light absorption in the reactor was the most collimated LED possible, in this case with a total viewing angle of 20°. The optimal reactor set-up uses the most reflective material preferably aluminum or silver to recuperate diverging light rays for the used wavelength. Furthermore, the wall thickness of the glass reactor should not be excessively large. In this case we saw no performance increase below 1.5 mm reactor thickness. Regarding reagents and absorbance, it is shown to best use a higher concentration and reduce the reactor length as this increases reactor performance under the condition that quantum yield is stable as function of concentration. Via the use of non-collimated light, it was determined that the entrance efficiency can be increased compared to a fully collimated light source, at the cost of reflection losses that increase with path length. Thus, the optimal parameters were determined to utilize co- and countercurrent illumination in the industrial context while keeping efficiency high.

References

1. Meir G, et al.,. J Adv Manuf Process. doi:10.1002/amp2.10044
2. Meir G, et al., J Adv Manuf Process. 2020;(February):1-16. doi:10.1002/amp2.10045