Scalability of 3D printed structured porous milli-scale reactors

Abstract

This study addresses the scalability of in-house designed, and 3D printed structured porous reactors for liquid-liquid reactions. The base structure of these porous reactors consists of cylindrical fibres in defined geometrical arrangements. Their scale-up was realized by increasing the reactor diameter by a factor of 1.5 and 2 respectively while keeping the fibre dimensions constant. Also, the effect of altering the fibre dimensions in proportion to the scale-up factor was assessed. The reactors were characterized in terms of their biphasic heat and mass transfer properties. In stratified flow, the scaled-up structured porous reactors exhibited high interfacial mass transfer coefficients (kLa) at residence times <10 s, whereas in Taylor flow an overall drop in kLa values was observed. Furthermore, the highest biphasic heat transfer coefficients were found for the structured porous reactors with a scale-up factor of 1.5. Moreover, the structured porous reactors were applied to industrially relevant reactions. For the oxidation of nonanol, the scaled-up reactors showed an overall drop in yield, nevertheless with two folds production rate at same pressure drop. For the relatively slow C-N cross-coupling reaction, larger yields were realized by arranging scaled-up reactors in series at same total residence time. Specifically, an arrangement of 8 reactors with a scale-up factor of 2 in series resulted in six times higher production rate than a conventional packed-bed reactor but without any additional pressure drop. For the considered range of residence times, keeping the fibre dimensions constant while increasing the reactor diameter was observed to be advantageous.