Convective acceleration of mass transfer in three-phase systems by pressure oscillations

✍ Scribed by J.C. Van Den Heuvel; I. Portegies Zwart; L.H.J. Vredenbregt

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 664 KB
• Volume: 51
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(96)00095-4

✦ Synopsis

Gas bubbles entrapped in catalyst particles subjected to hydrostatic pressure oscillations, e.g. during recirculation in loop reactors, will induce intrapardcle liquid flows, and thereby enhance mass transfer in excess of diffusion. This breathing particle' concept was clearly demonstrated in a gas-producing model system. At an amplitude of 0.3 MPa and a frequency of 3 Hz~ the activity was more than doubled as compared to the static pressure reference system. The experimental results could be modelled satisfactorily assuming axial dispersion of the internal liquid flow as the main mechanism to bring about acceleration. The calculated dynamic gas hold-up, being the only input variable, corresponded well with the measured value at constant pressure. From the experimental evidence and the model predictions, it is concluded that acceleration of mass transfer in gas-producing systems offers challenging ixxspectives for both heterogeneous catalysis and biological fermentations.