Design, characterization and application of continuous-flow photoreactors

This thesis explores the transition from batch to continuous-flow processing in photochemistry, focusing on reactor design, characterization, and application. This shift introduces unique challenges and operating conditions. The work presented emphasizes understanding factors affecting photoreactor operation, which is essential for reactor characterization, benchmarking, and scaling up. Photochemistry's expanding applications involve a wide range of reaction media, reactor geometries, light sources, and control requirements, making reproducibility a critical concern.
Chapter 1 provides a broad introduction to continuous-flow photochemistry and luminescent solar concentrators. Chapter 2 showcases a methodology to determine photon flux and the newly introduced one-dimensional parameter, effective optical path length, which enhances reactor characterization. The work uses radiometry and ray-tracing simulations, validated with batch photochemistry and applied to continuous-flow reactors, to improve photon-efficiency assessment photoreactors. Chapter 3 discusses novel 3D-printed reactors, addressing key challenges in photochemistry, while Chapter 4 introduces a method to convert microreactors into light-harvesting systems using luminescent solar concentrators. This method separates reactor design from solar applications, enabling easy dye replacement and rapid screening. In Chapter 5, a scaled-up solar-powered system is demonstrated, allowing automated off-grid operation with photovoltaic cells and feedforward control for product quality. Chapter 6 focuses on handling solids in continuous-flow systems, introducing a photoreactor that avoids clogging while operating in gas-liquid-solid environments.
This research highlights the importance of reactor characterization, light-source matching, and the handling of multiphase systems for the future development and scale-up of photoreactors.