(84b) Liquid Phase Back Mixing in Bubble Columns

Liquid phase back mixing in bubble columns

Linda Schlusemann^*1, Marcus Grünewald¹

* schlusemann@fluidvt.rub.de

¹ Ruhr-University Bochum, Chair of fluid processing, 44801 Bochum, Germany

1.    Motivation

Due to their simple design bubble columns are widely used in chemical, petrochemical industry and in biotechnology. Despite the simple geometry, the measurement of phase distribution and flow structure in multiphase columns is a major challenge. Especially back mixing effects have mainly been observed in computational fluid dynamic (CFD) simulations rather than in experimental studies. Therefore it is reasonable to invent an experimental setup to measure the back mixing and flow structure of the liquid phase in bubbles columns in industrial scale.

2.    Experimental studies

For the experimental development of the hydrodynamic a bubble column made of Plexiglas ® with an inner diameter of 290 mm and a height to diameter ratio of 14 (see fig. 1) is used. The column can operate in semi- batch and co- current flow. Water is used as continuous/liquid phase and nitrogen as gas phase.  

The measurement technique is a wire mesh sensor consisting of 32x32 measurement points in the cross section of the column. The flow structure of the liquid phase is investigated by adding acetic acid as a tracer to the liquid flow on the bottom of the column. The wire mesh sensor can measure the resulting increase in conductivity at each mesh point. This is how the flow structure in the cross section of the column can be determined.

3.    Goals

These experiments should help to build a model for the flow structure of the liquid phase in bubble columns.

This presentation includes a detailed description of the measurement technique and the experimental setup. Furthermore the first results of own experimental studies are presented and discussed.