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Fakultät BCI
Thesis Offer

Master Thesis: Development of a stochastic slug flow crystallizer model using Monte Carlo methods

  • Thesis offer
© Collin Johnson, TU Dortmund


Continuous crystallization offers several advantages over conventional batch crystallization in terms of operating costs, process control and flexibility. However, a narrow crystal size distribution, which is the objective of the crystallization, cannot be achieved in conventional continuous crystallizers given the high degree of backmixing. One realization of a continuous tubular concept without backmixing is the slug flow crystallizer (SFC) [1]. Here, backmixing is avoided by segmenting the process medium using air slugs.

Unfortunately, standard numerical approaches, cannot accurately represent systems exhibting a complete lack of backmixing. Therefore, a model for the continuous phase of the SFC based on a sequencing method [2] will be developed in this thesis. In the sequencing method, the different phenomena of the convection-diffusion-reaction equations are separated, resulting in potential diffusion-free solutions. Subsequently, the population balance equation (PBE) is solved using Monte Carlo simulations [3]. Due to the small number of crystals in the crystallizer, the crystal size distribution exhibits a large variation, which will be investigated using Monte Carlo methods.


  • Modeling of the SFC using the sequencing method
  • Implementation of the Monte Carlo simulation for the solution of the PBE
  • Investigation of the inherent uncertainty of the crystal size distribution


  • Student in the field of Chemical Engineering or related disciplines
  • Experience in modeling
  • Python experience is beneficial


[1] Termühlen, Maren, Matthias Markus Etmanski, Ines Kryschewski, Anne Cathrine Kufner, Gerhard Schembecker, and Kerstin Wohlgemuth. “Continuous Slug Flow Crystallization: Impact of Design and Operating Parameters on Product Quality.” Chemical Engineering Research and Design 170 (June 2021): 290–303.
[2] Renou, Stéphane, Michel Perrier, Denis Dochain, and Sylvain Gendron. “Solution of the Convection–Dispersion–Reaction Equation by a Sequencing Method.” Computers & Chemical Engineering 27, no. 5 (May 2003): 615–29.
[3] Van Peborgh Gooch, John R., and Michael J. Hounslow. “Monte Carlo Simulation of Size‐enlargement Mechanisms in Crystallization.” AIChE Journal 42, no. 7 (July 1996): 1864–74.


Beginning: As soon as possible

Duration: 6 months

  • Your work will be in English and you can communicate with your supervisor in English or German.
  • Please e-mail your application including your CV, BSc and MSc grades.
  • Please contact the responsible people for any further questions. All details can be discussed in a personal consultation.