Design and Characterization of a Scaled-up Ultrasonic Flow Reactor
Claire Delacour, Dwayne Savio Stephens, Cécile Lutz, Robert Mettin, Simon Kuhn
Abstract
Ultrasonic microreactors are increasingly applied to particle synthesis, crystallization processes, or organic synthesis involving solids because of the clogging prevention offered by ultrasound irradiation. However, the further application of this technology is limited by the scalability of ultrasonic flow reactors. In this work, we combined experiments and numerical simulations for the design of a scaled-up flow reactor. The reactor consists of a perfluoroalkoxy alkane (PFA) tubing immersed in a box to transmit the ultrasound and provide temperature control, to which six Langevin multifrequency transducers are attached. The acoustic pressure distribution was investigated to characterize the effect of ultrasound frequency and the transducer configurations on particle size distribution for the model reaction of barium sulfate synthesis. Operating the scaled-up reactor with six transducers at a frequency of 40 kHz resulted in an acoustic wave distribution with maximum acoustic pressures in the vicinity of the tubular reactor, thus leading to a small particle size distribution and consequently clogging prevention. The productivity of the scaled-up reactor was 14g/h barium sulfate at a remarkably low applied ultrasound power of 0.48W/mL, highlighting the efficient design and the further scale-up potential.