Modelling the Impact of Mass Transport in a Miniplant Photoreactor

The scale-up of photoreactions posses challenges due to the non-linear coupling of the radiation field with reaction kinetics and mass transport. A knowledge-based scale-up requires a sufficiently detailed theoretical description of these processes. In this work, a transient, two-dimensional photoreactor model is proposed and used to systematically investigate mass transport limitations in photoreactors, including the effect of transverse mass transfer through static mixers and the self-shadowing effect of the photoisomerization of spyropyrane. The proposed photoreactor model indicated that the installation of static mixers would increase the transverse dispersion by a factor of 600, which would allow the conversion to be tripled in an up-scaled photoreactor. Furthermore, a shrinking reaction zone was observed when increasing the light power, emphasizing the importance of mass transport for scaling photoreactors.