(62d) Project “Multi-Phase” – Gas Holdup of Bubble Columns in a Multidimensional Space

Project “Multi-Phase” – gas holdup of bubble columns in a multidimensional space

Philipp Rollbusch^1*, Linda Schlusemann^2*,  Marc Becker¹, Martina Ludwig¹, Marcus Grünewald²

* Philipp.Rollbusch@evonik.com, Linda.Schlusemann@fluidvt.rub.de

¹ Evonik Industries AG, Process Technology & Engineering, 45772 Marl, Germany

² Ruhr-University Bochum, Chair of fluid processing, 44801 Bochum, Germany

Bubble columns are widely used for important technical multiphase processes in chemical, biochemical and petrochemical industry. These columns can be used as contactors, but also for absorption processes and as reactors. The Annual production in bubble column reactors, in terms of intermediates and end products, for the production of terephthalic acid, acetic acid, oxo alcohols, acetone, and hydrogen peroxide amounts to over 30 million metric tons.

Due to the complex mathematical description and intrusive experimental measurement methods, the behavior of multiphase flow is not completely understood. A consequence of this is that the design and scale-up especially of bubble columns are difficult and inherits uncertainties which may lead to non-optimal reactor designs. Therefore more research has to be done to clarify important dependencies of design parameters and hydrodynamics in bubble columns especially in industrial relevant scale and at process conditions.

This presentation includes an overview of gas holdup in bubble columns. Data from literature as well as own experimental results in bubble columns of different scale will be presented. Results regarding radial gas holdup profiles obtained via a low intrusive wire-mesh sensor used in a DN300 bubble column at atmospheric pressure and a DN330 column at elevated pressure will be presented and discussed. Furthermore axial gas holdup profiles measured by the use of pressure difference sensors will also be discussed. Besides gas density the sparger design may also influence the gas holdup. The effect of different sparger geometries was also investigated with the help of a wire-mesh sensor and will be presented.

The Multi-Phase project (full title: Increasing Energy Efficiency and Reducing Greenhouse Gas Emissions by Multiscale Modeling of Multiphase Reactors) is supported by the BMBF under support no. 01RC1102.