Jürgen Fitschen, M.Sc.

Eißendorfer Str. 40, Building N, Room 1.083

Telephone +49 40 42878-2031

E-Mail: Jürgen Fitschen, M.Sc.


Research

Large Scale Bioreactors – Insight Into a Black Box

 

In any case of mammalian cell expression systems it is of vital importance to ensure ideal growth conditions. In general, to achieve high product qualities and efficiencies, a constant feed and oxygen supply and a homogeneous mixing behavior have to be guaranteed during the entire process time as well as overall upstream processes. For a reliable design and scale up a profound understanding of hydrodynamics and mass transfer is required.

At the Institute of Multiphase Flows (IMS) at the Hamburg University of Technology various studies have been performed to study the influence of different operation conditions as well as stirrer geometries on mixing efficiency, mass transfer performance and power input on laboratory (0.002 and 0.03 m3) and industrial scale (15 m3). This work gives deep insights into the hydrodynamic behavior and a characterization of an industrial scale aerated stirred tank reactor." 


Education

Graduate Teaching Assistant

  • Fluid Mechanics Process Engineering


Supervised Theses

  • "Hydrodynamische Optimierung eines Großpumpwerkes zur Verbesserung der Sandfördereigenschaften", Lisa Christin Watter, Master thesis, 2021
  • "Experiemental investigation of the influence of counter-diffusion on the volumetric mass transfer coefficient in aerated stirred tank reactors", Ingrid Haase, Master thesis, 2021
  • "Experimental Determination of the Oxygen Mass Transfer Performance and the Bubble Size Distribution of a 200 L Single-Use Aerated Stirred Tank Reactor", Rajat Srivastava, Master thesis (supervision in cooperation with Marc Maly), 2021
  • "Experiemental investigation of the local gas distribution of different stirrer configurations in a 30L aerated stirred tank reactor", Kevin Ertelt, Bachelor thesis, 2020
  • "Desgin and Construction of a flapping foil based reactor geometry and experimental evaluation of the mixing performace of different foil geometries and stirring pattern", Jonathan Garlipp, Bachelor thesis, 2020
  • "Experimental investigation of the influence of modified Rushton turbines on power input and mass transfer performance in a 30 L stirred tank reactor", Ingrid Haase, Project work, 2020
  • "Experimental Evaluation of Scale-Up Strategies for Oxygen- and Carbondioxid mass transfer of aerated stirred tank reactors", Vathsalya Pabbathi, Project work, 2020
  • "Experimental Determination of Power Input and Mixing Performance of Various Stirrer Combinations in a Lab- and Industrial Scale Aerated Stirred Tank Reactor by use of a self-constructed and 3D printed bottom driven magnetic stirrer", Benjamin Bremecker , Bachelorthesis, 2019
  • "Visualisation of streamlines in aerated stirred tank reactors - a feasibility study for the application of 2D-PTV in industrial scale", Marcus Schewe, Bachelor thesis, 2019
  • "Experimental Determination of Shear Rate in a 3L Aerated Stirred Tank Reactor by Means of Shear Sensitive Particles", Zeynep Persin, Master thesis, 2019
  • "Experimental Determination of Power Input and Mixing Characteristics of Various Stirrer Combinations in a Lab-Scale Aerated Stirred Tank Reactor", Vincent Bernemann, Bachelor thesis, 2019
  • "Experimental Determination of Bubble Size Distributions and Oxygen Mass Transfer Performances to Evaluate Scale-Up Rules for Aerated Stirred Tank Reactor in Lab- and Pilot-Scale", Ezgi Arslanturkoglu, Master thesis, 2019
  • "Design and Construction of a 30 L Aerated Stirred Tank Reactor on a Pilot Scale and Experimental Determination of Power Input and Mixing Performance for Different Stirrer Configurations", Benjamin Cardenas, Master thesis, 2019
  • "Numerische Simulation der Mischcharakteristik eines Rührkesselreaktors im industriellen Maßstab mittels verschiedener Turbulenzmodelle", Christian Weiland, Master thesis, 2019
  • "Experimental Determination of Local Bubble Size Distributions in Aerated Stirred Tank Reactor on a Pilot Scale", Lisa Christin Watter, Project work, 2018
  • "Experimenteller Vergleich von dynamischen und stationären CO2 Stoffübergangsmessungen in begasten Rührkesselreaktoren im Labor- und Industriemaßstab", Kai Heitmann, Master thesis, 2018
  • "Experimentelle Untersuchung zum Gasgehalt begaster Rührkesselreaktoren im Industriemaßstab", Xiye Zhou, Bachelor thesis, 2018
  • "Experimental Determination of Relative Humidity in the Exhaust Gas Stream of an Industrial Scale Aerated Stirred Tank Reactor", Ezgi Arslanturkoglu, Project work, 2018

 


Oral Presentations

2022

  • Fitschen, J.; Hofmann, S.; Kuschel, M.; Hoffmann, H.; Wucherpfennig, T.; Schlüter, M.:, Characterization of Heterogeneities in Stirred Tank Reactors by Means of 4D Particle Trajectories, 26th CHISA, 2022, oral presentation
  • Fitschen, J.; Kuschel, M.; Hofmann, S.; Hoffmann, H.; von Kameke, A.; Wucherpfennig, T.; Schlüter, M.:, Characterization of Heterogeneities in Stirred Tank Reactors by Means of 4D Particle Trajectories and Numerical Flow Simulations, NAMF Mixing XXVII (virtual), 2022, oral presentation
  • Hofmann, S.; Vernier-Lambert, H.; Meriguet, S.; GopalSingh, P.; Fitschen, J.; Neubauer, P.; von Lieres, E.; Ferguson, M.; Schlüter, M.: Assessment of Lagrangian Sensor Particle Designs in a Transparent 15,000 L Acrylic Glass Bioreactor, 7th BioProScale Symposium, organized by Prof. Neubauer (TU Berlin), Langenbeck-Virchow-Haus, Berlin 2022, oral presentation
  • Gaugler, L.; Mast, Y.; Fitschen, J.; Hofmann, S.; Schlüter, M.; Takors, R.: Development of a single multi-compartment bioreactor (SMCB) for CHO scale-down studies in a heterogeneous cultivation environments, 7th BioProScale Symposium, organized by Prof. Neubauer (TU Berlin), Langenbeck-Virchow-Haus, Berlin 2022, oral presentation
  • Fitschen, J.; Hofmann, S.; Hoffmann, H.; Kuschel, M.; Wucherpfennig, T.; Schlüter, M.:, Lokale Mischzeitverteilung in begasten Rührkesselreaktoren im Labormaßstab, Jahrestreffen der ProcessNet-Fachgruppen Computational Fluid Dynamics + Mischvorgänge + Agglomerations- und Schüttguttechnik, 2022, oral presentation
  • Weiland, C; Hofmann, S.; Fitschen, J.; von Kameke, A.; Hoffmann, M.; Schlüter, M.: Numerische Simulation Lagranger Partikeltrajektorien und Charakterisierung des Partikelfolgevermögens in einem 3 L Rührkesselreaktor, Jahrestreffen der ProcessNet-Fachgruppen Computational Fluid Dynamics + Mischvorgänge + Agglomerations- und Schüttguttechnik, 2022, oral presentation
  • Hofmann, S.; Weiland, C.; Fitschen, J.; v. Kameke, A.; Hoffmann, M.; Schlüter, M.: Vergleich von experimentellen und numerischen Untersuchungen zur Abschätzung des Folgevermögens verschiedener Lagrange’scher Partikel in der Bioreaktorströmung,Jahrestreffen der ProcessNet-Fachgruppen Computational Fluid Dynamics + Mischvorgänge + Agglomerations- und Schüttguttechnik, 2022, oral presentation

2021

  • Fitschen, J.;  von Kameke, A.; Hoffmann, H.; Wucherpfennig, T.; Schlüter, M.:, Experimental Investigation of Compartment Formation in Aerated Stirred Tank Reactors, Dispersed Two-Phase Flows 2021 (virtual), 2021, oral presentation
  • Fitschen, J.; Kuschel, M.; Hofmann, S.; Hoffmann, H.; von Kameke, A.; Wucherpfennig, T.; Wutz, J.; Schlüter, M.:, Validation of Numerical Flow Simulations in a 3 L Stirred Tank by Means of Real 4D Particle Trajectories, ECCE 13 & ECAB 6 (virtual), 2021, oral presentation
  • Hofmann, S.; Gaugler, L.; Fitschen, J.; v. Kameke, A.; Schlüter, M.; Takors, R.: Lagrangian Particle Tracking and Bioreactor Compartmentalization as Novel Scale-up Tools for Biopharmaceutical Processes, ECCE 13 & ECAB 6 (virtual), 2021, oral presentation
  • Fitschen, J.;  Hofmann, S.; Hoffmann, H.; von Kameke, A.; Schlüter, M.:, Measurement of Lagrangian Tracks in a 3 L Stirred Tank Reactor using 4D Particle Tracking Velocimetry with Shake-the-Box, ISPIV 21 (virtual), 2021, oral presentation
  • Fitschen, J.: Characterization of Compartments in Stirred Tank Reactors: Insights from Mixing and 4D-Particle Tracking Experiments, DSP-Doktorandenseminar, 2021, oral presentation
  • Fitschen, J.;  Hofmann, S.; Hoffmann, H.; Wucherpfennig, T.; Wutz, J.; Schlüter, M.:, New Method for the Characterization of Shear Sensitive Mixing Processes in Modern Biotechnology, ACHEMA Pulse 21 (virtual), 2021, oral presentation
  • Fitschen, J.; Kuschel, M.; Hofmann, S.; Hoffmann, H.; von Kameke, A.; Wucherpfennig, T.; Wutz, J.; Schlüter, M.:, Validierung von numerischen Strömungssimulationen in einem 3L Rührkesselreaktor mittels 3D Partikel Trajektorien, Jahrestreffen der ProcessNet-Fachgruppen Computational Fluid Dynamics und Mehrphasenströmungen, 2021, plenary lecture

2019

  • Fitschen, J.; Rosseburg, A.; Wucherpfennig, T.; Wutz, J.; Schlüter, M.: Visualization of Mxing Performance and Measurement of Power Input in Aerated Stirred Tank Reactors on a Lab and Industrial Scale, 12th European Conference of Chemical Enginnering (ECCE 2019), Florence, Italy, 2019, oral presentation 
  • Fitschen, J.; Rosseburg, A.; Wucherpfennig, T.; Wutz, J.; Schlüter, M.: Visualization of Mixing Performance and Measurement of Power Input in Aerated Stirred Tank Reactors- Comparison of Laboratory and Industrial Scale, 10th International Conference on Multiphase Flow, Rio de Janeiro, Brasil, 2019, oral presentation
  • Fitschen, J.; Rosseburg, A.; Wucherpfennig, T.; Wutz, J.; Schlüter, M.: Bioprocesses Made Transparent - Stirring on Industrial Scale - Deep Insights and Characterization, Jahrestreffen der ProzessNet-Fachgruppen Mischvörgänge, Trocknungstechnik und Wärme- und Stoffübertragung, Essen, 2019, oral presentation


Poster Presentations

  • Hofmann, S.; Weiland, C.; GopalSingh, P.; Kamp, M.; Fitschen, J.; v. Kameke, A.; Hoffmann, M.; Schlüter, M.: Experimental and numerical determination of lifelines in a 3 L, 200 L and 15000 L stirred tank reactor, MIXING XXVII, North American Mixing Forum (NAMF), Online Conference 2022
  • Hofmann, S.; Fitschen, J.; v. Kameke, A.; Schlüter, M.: Multiscale Experimental Analysis of Lifelines in Bioreactors 1. Hamburg-Bochumer Mehrphasensymposium, Hamburg/Bochum, Online Conference, 2020
  • Rosseburg, A., Fitschen, J., Wutz, J., Wucherpfennig, T., Schlüter, M., „Influence of local flow structure on the mixing behaviour within an aerated 12 000L stirred tank reactor”, Jahrestreffen der ProcessNet Fachgruppe Mischvorgänge, Munich 2018
  • Fitschen, J.; Rosseburg, A.; Wucherpfennig, T.;Wutz, J.; Schlüter, M.: Verfahren zur optischen Bestimmung von lokalen Konzentrationsgradienten in einem gläsernen 15 kL begasten Rührkesselreaktor., Gemeinsamen Jahrestreffen MPH, WSUE & CFD, Bremen, Germany, 2018
  • Fitschen, J.; Rosseburg, A.; Wucherpfennig, T.; Wutz, J.; Schlüter, M.: Visualization of mixing in an acrylic 12000L aerated stirred tank reactor, 10th World Congress of Chemical Engineering, Barcelona, Spain, 2017


Publications

[154746]
Title: Novel Evaluation Method to Determine the Local Mixing Time Distribution in Stirred Tank Reactors.
Written by: Fitschen, J.; Hofmann, S.; Wutz, J.; Kameke, A. v.; Hoffmann M.; Wucherpfennig T.; Schlüter, M.
in: <em>Chemical Engineering Science: X</em>. May (2021).
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DOI: https://doi.org/10.1016/j.cesx.2021.100098
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Abstract: Stirred tank reactors are frequently used for mixing as well as heat- and mass transfer processes in chemical and biochemical engineering due to their robust operation and extensive experiences in the past. However, for cell culture processes like mammalian cell expression systems, special requirements have to be met to ensure optimal cell growth and product quality. One of the most important requirements to ensure ideal transport processes is a proper mixing performance, characterized typically by the global mixing time or the dimensionless global mixing time .As an evaluation method for mixing time determination, the time is usually determined until a tracer signal (e.g. conductivity) has reached a constant value after a peak has been introduced (e.g. by adding a salt). A disadvantage of this method is, that the position of tracer feeding as well as the position of the probe significantly influences the detected mixing time. Further on, the global mixing time does not provide any information about the spatial and temporal ”history” of the mixing process to identify areas that are mixed poorly or areas that form stable compartments. To overcome this disadvantage, a novel image analysis will be presented in this study for the detailed characterization of mixing processes by taking into account the history of mixing. The method based on the experimental determination of the local mixing time distribution by using a multi-color change caused by a pH-change in a bromothymol blue solution. A 3 L transparent stirred tank reactor is used for the benchmark experiment. To demonstrate the suitability of the new characterization method for the validation of numerical simulations, a calculation with a commercial Lattice-Boltzmann approach (M-Star CFD) has been performed additionally and evaluated regarding mixing time distributions. The exemplary application of image analysis to a numerical mixing time simulation shows good agreement with the corresponding experiment. On the one hand, this shows that the method can also be interesting for numerical work, especially for experimental validation, and on the other hand, this allows much deeper insights into the mixing behavior compared to conventional mixing criteria. For example the new method enables the characterization of mixing on different scales as well as the identification of micor- and macroscopic flow structures. The strong influence of the acid to base ratio on mixing time experiments becomes clearly visible with the new method.