Flat-plate mesophotoreactor with a serpentine channel and inclined baffles for balancing mixing performance and reaction throughput†

This study aims to address the main challenges encountered during the scale-up of flat-plate microreactors in photochemical processes: the decline in mixing and mass transfer efficiency, and the decrease in light energy utilization. Although microreactors have been widely studied for their efficient mass transfer and light energy utilization, the degradation of their performance during scale-up has limited their application in industrial production. Here, a strategy was explored to enhance the mixing efficiency by introducing inclined baffle structures within the mesoscale channel. The performances of a conventional 1 mm microreactor and an optimized mesoreactor with baffles were compared in the homogeneous photochemical reaction. The results indicated that under similar residence times, the yields of both reactors were nearly the same, but the reaction flux was increased by about 180 times compared to the microreactor. The characteristic mixing time (t_m) and the second Damköhler number (Da_II) for the mesoscopic reactor with baffles were similar to those of the microreactor. This result demonstrates the validity of the scale-up strategy in maintaining high mixing and mass transfer efficiency. The performance of the mesoreactor with baffles in heterogeneous reactions was also investigated, and high yields were achieved by extending the length of the reactor channel. The photochemical space time yield (PSTY) of the baffled mesoreactor with extended channels almost doubles that of the microreactor. This study provides an effective method for scaling up plate-type photochemical microreactors, opening up new possibilities for the application of microreactors in industrial production.