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A simple model for determining potential bottlenecks of a photoreactor setup focusing on the photon fluxes is presented. The application of the concept can reveal optimization potentials and gives insights into the sensitivity of the reactor setup to different optimization possibilities. The introduced model benefits from the concept of using only data already available from optimization studies of the process conditions. Applying the introduced concept to the characterization of a previously developed modular organic light-emitting diode reactor setup revealed great optimization potentials, especially with respect to the external photonic efficiency. Interestingly, the attempt to enhance the external photonic efficiency by increasing the projection area of the reactor did not provide any improvement. This is attributed to a significant influence of reflection and scattering within the setup.

The aim of this study was to accurately quantify the benefit of adding extra layers to a capillary flow‐photoreactor using actinometry. A self‐built 3D‐printed FEP cap‐ illary mount was designed and each of the layers was evaluated separately. Experimental results showed that additional capillaries can be regarded as an augmented optical path length and that reflection and scattering are of minor importance for stacking of capillaries. To cope with the problem of precipitation of the ferrioxalate actinometer in intensified reactors, a new experimental method of conducting actinometric measurements with pulses was investigated and showed reasonable agreement. To make the results comparable to other literature‐known, mostly also improvised reactor setups, appropriate figures of merit (productivity, space time yield, energy efficiency and external photon efficiency) were evaluated.

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...

Evaluating the efficiency of newly designed photoreactors is crucial for systematic development and optimization of photochemical processes. A suitable tool is actinometry, prominently represented by the most widely studied and applied ferrioxalate system. However, such measurements show reproducibility problems in the data consistency. This study scrutinizes these issues and approaches an experimental elucidation. An application limit for the ferrioxalate actinometer under intense irradiation was identified and experimentally validated. A drop of the quantum yield at high incident photon fluxes, generating high local concentrations of carboxyl radicals, leads to systematically wrong measurements. For reliable measurements with the ferrioxalate actinometry, a continuous operation mode or extensive mixing should be ensured.