Felix Kexel, M.Sc.

Eißendorfer Str. 40, Building N, Room 1.082

Telephone +49 40 42878-4663

E-Mail: Felix Kexel, M.Sc.


Research

DFG Priority Project 1740 - "Reactive Bubbly Flows"

 

How are the diffrent timescales of fluid dynamic mixing, mass transfer and reaction kinetics imapcting the yield and selectivity of competitive-consecutive gas-liquid reactions?

Applying measuring techniques as Particle Image Velocimetry (PIV), Laser Induced Fluorescence (LIF) or imaging UV-VIS Spectroscopy to obtain information on velocity and concentration fields of primary and secondary products in the wake of rising gas bubbles


Education

Graduate Teaching Assistant

  • Fluid Mechanics in Process Engineering (Winter term)

 


Supervised Theses

Current Thesis:
  • "Experimentelle Untersuchung des Einflusses der Fluiddynamik auf eine kompetitiv-konsekutive Reaktion in einer Hele-Shaw Zelle" [Working Title], Rene Weglewski, Master thesis
Finished Thesis:
  • "Taylor Bubbles in Organic Solvents", Sina Bertram, Bachelor thesis, 2022
  • "Computation of Unsteady Mass Transfer in Bubble Wakes by Means of 2D Lagrangian Analysis", Lotta Kursula, Master thesis, 2022
  • "Anwendung der Penetrationstheorie auf lokale Stofftransportprozesse an Taylor Blasen", Benjamin Rahimian, Bachelor thesis, 2022
  • "Characterization of the fluid dynamic properties of a Methanol based chemical reaction", Noah von Schnitzler, Bachelor thesis, 2021
  • "Taylor Bubble Generation Using a Selonoid Valve", Tarlan Ramazanli, Project Work 2021
  • "Detailed investigations of bubble trajectories in clean and contaminated systems", Sam Dors, Bachelor thesis, 2020
  • "Determination of mass transfer coefficients from single Taylor bubbles in contaminated systems – a study for industrial applications", Aaron Kaulbarsch, Bachelor thesis, 2019
  • "Experimentelle Analyse des Einflusses von organischen Lösemitteln auf die Hydrodynamik von Taylorblasen am Bespiel von Acetonitril", Carolin Lohmann, Bachelor thesis, 2019


Oral and Poster Presentations

  • Kexel, F.; Bertram, S.; Mehrbach, T.; von Kameke, A.; Hoffmann, M.; Tomiyama, A.; Schlüter, M.: "Influence of Taylor Bubble Shapes on Wake Structures" 4th International Symposium on Multiscale Multiphase Process Engineering, Berlin, 2022, poster presentation
  • Radmehr, A; Kexel, F.; von Kameke, A.; Hoffmann, M.; Schlüter, M.: "Local Velocity Fields at Taylor Bubbles in Methanol" 11th Workshop Chemical and Biological Mico Laboratory Technology 2022, Ilmenau, 2022, oral presentation
  • Kexel, F.; von Kameke, A.; Hoffmann, M.; Schlüter, M.: "Fluid Dynamics of Taylor Bubbles in Organic Solvents" ProcessNet Jahrestreffen Mehrphasenströmungen, Mechanische Flüssigkeitsabtrennung & Zerkleinern und Klassieren 2022, virtual, 2022, oral presentation
  • Kexel, F.; von Kameke, A.; Hoffmann, M.; Schlüter, M.: "Investigation on Velocity and Concentration Fields at Taylor Bubbles in a Reactive Bubbly Flow" Dispersed Two-Phase Flows 2021, virtual, 2021, oral presentation
  • Kexel, F.; von Kameke, A.; Hoffmann, M.; Schlüter, M.: "Influence of Fluid Dynamics on the Selectivity of Competitive Consecutive Gas Liquid Reactions" 13th European Congress of Chemical Engineering (ECCE13), virtual, 2021, oral presentation
  • Kexel, F.; von Kameke, A; Hoffmann, M.; Schlüter, M.: "Optimization of Chemical Reactions with Tailored Flow Strucures" ProcessNet Jahrestreffen Reaktionstechnik 2021, virtual, 2021, poster presentation
  • Kexel, F.; von Kameke, A; Hoffmann, M.; Schlüter, M.: "Investigation of the influence of fluid dynamics on the selectivity of fast gas-liquid reactions by means of high speed imaging UV/VIS spectroscopy at a Taylor bubble setup" ProcessNet Jahrestreffen Mehrphasenströmungen & CFD 2021, virtual, 2021, poster presentation
  • Kexel, F.; von Kameke, A.; Colombi, R.; Rüttinger, S.; Hoffmann, M.; Schlüter, M.: "Inverstigation of Reactive Mass Transfer Processes at Single Rising Bubbles by Means of Time-Resolved Scanning Laser Induced Fluorescence" 12th European Congress of Chemical Engineering (ECCE12), Florence, Italy, 2019, oral presentation 
  • Kexel, F.; Rüttinger, S.; Kastens, S.; von Kameke, A.; Oßberger, M.; Hoffmann, M.; Schlüter, M.: "Does the wake structure in bubbly flows affect yield and selectivity of a competitive consecutive reaction? – A Taylor-Bubble study" ProcessNet Jahrestreffen Reaktionstechnik & Mehrphasenströmungen 2019, Würzburg, 2019, oral presentation


Publications

[158828]
Title: The influence of fluid dynamics on the selectivity of fast gas–liquid reactions in methanol.
Written by: Kexel, F.; Kameke, A.v.; Hoffmann, M.; Schlüter, M.
in: <em>Chemical Engineering and Processing - Process Intensification</em>. (2021).
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DOI: https://doi.org/10.1016/j.cep.2021.108650
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Abstract: One important strategy for process intensification is the enhancement of yield and selectivity in fast gas–liquid reactions, like oxidations, hydrogenations or halogenations. However, the interplay between fluid dynamics and competitive chemical reactions has not yet been understood to an extent that allows tailoring the flow and concentration fields for intensified reactions. To understand the interplay, the fluid dynamic conditions surrounding Taylor bubbles rising in an organic solvent are studied and compared to data of aqueous systems from the literature. The local flow fields are measured using Particle Image Velocimetry (PIV) and compared to spectroscopically derived selectivity data of a competitive consecutive gas–liquid reaction. The general rising behavior of Taylor bubbles in methanol is confirmed to be similar to those of bubbles in aqueous systems. However, as surface active agents do not affect the interface mobility in organic solvents, the local flow structures in the bubble wake differ significantly from those of bubbles rising in water, impacting the mixing behavior. Finally, the flow fields are compared to the concentration fields of the main and side products. Thereby, a decisive influence of the fluid dynamics on yield and selectivity becomes apparent, unveiling the potential for process intensification.