Characterization and optimization of the translucent monolithic photoreactors and comparison with other photoreactors

Abstract

Photochemical reactions have a couple of advantages compared to thermochemical reactions such as lower energy usage, higher selectivity, and access to new reaction pathways. Despite these advantages, photochemical reactions are rarely used in industry due to the limited scalability, caused by the photon and mass transfer limitations. It is hypothesized that a new reactor design can overcome these limitations by utilizing microchannels that are organized in a structured way. This reactor design is known as the translucent monolithic reactor. The purpose of this research is to characterize this reactor and compare it to other photochemical reactors. The monolithic reactor was characterized by finding its optimal operating point using the model reaction of singlet oxygen with 9,10-diphenylanthracene. This was done by studying the influence of parameters such as light intensity, flow rate, and concentration of the photosensitizer on the conversion, STY, and PSTY. The results at these conditions were compared to the data of a batch experiment and other photoreactors such as the FFPM and LSC-PM. Finally, the first steps towards slug flow within the monolithic reactor were performed. The monolithic reactor with a conversion of 80%, STY of 1.14 mmol/l·min, and PSTY of 0.27 mol/day·kW was 26 times more productive than the reaction performed in batch but 6.6 times less energy efficient. It also was 20 times more productive and 13 times more energy efficient compared to the FFPM and 6.3 times more productive than the LSC-PM.