Radiometric measurement techniques for in-depth characterization of photoreactors – part 1: 2 dimensional radiometry‡

This contribution presents a spatially resolving radiometric scanning method for the evaluation of the radiation field of photochemical reactors. By moving a calibrated spectrometer, a virtual canvas is created, capturing a UV/vis spectrum for every grid position. The measurements can be displayed as heatmaps, visualizing the received photon flux per measurement point or another property of the captured spectrum. This allows for an in-depth analysis of the radiation field to understand radiometric characteristics of the investigated setup. A perfluoroalkoxy alkane (PFA) capillary reactor system with one or two layers of capillaries was used to demonstrate the capabilities of the method. For a setup with two layers it is found that the first layer absorbs the majority of the incident photons (50%) whereas the second layer is absorbing 9%. The presented method allows for a sophisticated analysis of real photoreactors as the fundament for the development of highly efficient photoreactor designs and scale-up.