Investigation of Mass Transfer and Hydrodynamics in a Model Bubble Column

Abstract

Gas-liquid mass transfer in bubble columns is strongly influenced by the flow field in the column. The underlying transport processes are often the limiting factor. Since bubble columns are widely used in the chemical process industry, it is essential to quantify how the dispersed gas can come into reaction with the liquid phase through gas-liquid mass transfer. CO 2 bubble swarms in a cylindrical model bubble column are considered. Optical measurement methods are used for the nonintrusive measurement of velocity and pH change, resulting from the dissolution of CO 2 in the liquid phase. The mean and fluctuating velocity components in the center plane of the column as well as the time-dependent pH fields in this plane are determined. From these quantities, derived values characterizing the mass transfer from gaseous CO 2 to the liquid phase can be calculated.

Laser‐Induced Fluorescence in Multiphase Systems

“…The bulk phase grey level I 0 is then no longer one global value, but it depends on the measurement position and can vary depending on the relative position to the interface where the reflections arise. To overcome the reflection at the interface, the use of two dyes can be helpful, even though it makes the experiments, but in particular, the image processing steps afterwards remarkably more complex . One dye is then used as a reference (since it is not sensitive for the transferred species and can therefore also eliminate the errors due to unstable laser pulses), while the other one indicates the mass transfer.…”

Reaction Systems for Bubbly Flows

“…For further progress in evaluating the chemical differences when varying the solvent or the system, which is activated or changed by the gas, the basic environment of the actual multiphase system should be investigated first. Interesting factors like the bubble velocities, sizes and rising behaviour is usually measured in a water/CO 2 system …”

“…The rising bubbles in a bubble column were also analysed by a high‐speed PIV camera , , . The column had a diameter of 0.14 m and a filling height of 0.73 m and was made from acrylic glass with a thickness of 4 mm (Figure ).…”

“…Experimental setup for PIV (a) with high‐speed camera (1) high‐speed laser (2), light‐sheet optics (3), bubble column (4); (b) measurement windows. Reproduced from ref …”

Modeling an Airlift Reactor for the Growing of Microalgae

“…Bubble column reactors are widely used in the chemical and biochemical industries due to their high mass and heat transfer rates [1]. These reactors are usually formed by a cylindrical or rectangular vessel which has an air injection at the bottom, causing the generation of bubbles [2 -6].…”