Reactive bubbly flows
Sub-project: Experimental investigation of hydrodynamics, mass-transfer and reaction in bubble swarms with ultrafast X-ray tomography and local probes
For reactive processes, bubble column reactors, which are mainly used in the chemical industry, are operated in a gas-dispersed two-phase flow. In such systems a complex relationship between hydrodynamics, mass transfer and reaction prevails, which determine the reaction progress and, thereby, yield and selectivity of the chemical processes. Simple reactor models are usually not able to describe these phenomena. Local parameters, such as gas holdup, bubble size distribution and bubble induced turbulence, become more important in systems with high gas density. In particular, the influence of bubble induced turbulence on the structure of bubble swarms, the resulting mass transfer in the liquid phase and the corresponding distribution of the reactive species are so far insufficiently studied due to lack of proper measurement techniques.
The aim of this project within the frame of the DFG Priority Program SPP1740 (link: www.dfg-spp1740.de) “Influence of Local Transport Processes on Chemical Reactions in Bubble Flows” is the experimental investigation of hydrodynamics in bubbly flows and their influence on the chemical absorption in a lab-scale bubble column (100 mm). The ultrafast X-ray computed tomography is used to study flow structure and bubble swarm dynamics. Hot-wire anemometry is utilized to measure liquid phase velocities and turbulence parameters.
For the chemical absorption of CO2 in NaOH, wire-mesh sensor measurement technique is utilized for the first time to measure local species concentration and to capture local mass transfer rates in the cross-section of the column. The collected data serve as benchmark data for the validation of numerical flow models and, in turn, these data allow a better understanding of the interaction between hydrodynamics, mass transfer and chemical reaction.
TU Hamburg Harburg, LMU München, Universität Stuttgart, Otto-von-Guericke-Universität Magdeburg
German Research Foundation (DFG, HA 3088/8-1)
- R. Kipping, H. Kryk, E. Schleicher, M. Gustke, U. Hampel
Application of wire-mesh sensor for the study of chemical species conversion in a bubble column
Chemical Engineering & Technology 40, 8, 1425-1433 (2017)
- R. Kipping , E. Schleicher, H. Kryk, U. Hampel
Characterization of a chemical reaction in a bubble column using wire-mesh sensor and ultrafast X-ray CT
Proceedings 8th World Congress on Industrial Process Tomography (WCIPT8), 24.-26. September 2016, Iguassu Falls, Brasilien (2016)
- R. Kipping, H. Kryk, U. Hampel
Experimental investigation of mass transfer of CO2 bubbles with ultrafast electron beam X-ray tomography
FERMaT-SPP1740-Symposium, 06.-08. June 2016, Toulouse, Frankreich (2016)