251312 Hydrodynamics and Mass Transfer In the Horizontal Rotating Foam Stirrer Reactor

Wednesday, October 31, 2012: 4:15 PM
316 (Convention Center )
Maria A. Leon1, Rick J. Maas1, André Bieberle2, Markus Schubert3, T. Alexander Nijhuis1, John van der Schaaf1, Uwe Hampel3 and Jaap C. Schouten1, (1)Laboratory of Chemical Reactor Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, (2)Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf , Dresden, Germany, (3)Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany

The rotating foam stirrer reactor is a novel type of multi-phase reactor where highly open-celled materials, solid foams, are used both as a catalyst support and as a stirrer. One of the advantages of rotating foam stirrer reactors compared to e.g. slurry reactors is the absence of a catalyst separation step. Moreover, in the standard foam stirrer configuration, i.e., the foam structures (blades or donut-shaped foam blocks) are mounted on a vertical shaft, the formation of finely dispersed bubbles and the fast refreshment of the catalyst surface lead to better mass transfer rates.

In this work, a new foam stirrer design is presented. A donut-shaped foam block is mounted on a horizontal shaft. Using gamma-ray tomography, the hydrodynamics of the system is described. When the reactor is partially filled with liquid, a “spray regime” is observed which leads to the formation of fine liquid droplets and fine gas bubbles enhancing the gas-liquid mass transfer rate. Furthermore, due to the centrifugal forces at high rotational speeds, the gas is separated from the catalyst only by a very thin liquid film. This enhances the liquid-solid mass transfer of the gas reactant, which is often the limiting component in hydrogenation or oxidation reactions. Mass transfer measurements will be discussed for different operation conditions.

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See more of this Session: Multiphase Reaction Engineering II
See more of this Group/Topical: Catalysis and Reaction Engineering Division