Final Thesis

Implementation of an online-tool for liquid-liquid extraction columns based on population balances in Python

Key Info

Basic Information

Fluid Process Engineering
Focus/Key Topic:


The main objective of liquid-liquid extraction is an effective mass transfer between a dispersed (mostly) organic and a continuous (mostly) aqueous phase. The extraction device’s performance can be characterized by the mass transfer between the phases, which results from an interaction of multiple simultaneous phase phenomena. Thus, extraction research has been focusing on the development of numerous models to describe phase interactions (mass transfer, drop sedimentation) as well as individual phenomena appearing in the disperse phase (coalescence, breakage). Rigorous models of these phenomena and the prediction of their superposition are essential for the simulation of an extraction process. Thereby, the dispersed phase is balanced by so-called population balances. The evaluation of the latter is numerically challenging, thus, has demanded a considerable amount of research in the last decades. In this framework, models with a simplified (ReDrop) and a more rigorous (Compartment Model) degree of detail of the hydrodynamics have been developed at the FVT. However, the numerical evaluation of the resulting equation systems requires a simulation time that does not allow an online application of these tools.

The main motivation for this thesis is the necessity for a rigorous simulation tool, which represents a trade-off between speed and accuracy. For this purpose, a promising, simplified model for solving the population balance has to be implemented [3]. Suitable models for the description of the disperse phase phenomena and the interaction between the phases shall be selected and implemented. Furthermore, the separation behavior of the column shall be visualized. Experimental results from literature should be reproduced and the separation performance of simultaneous running experiments (not part of the task) shall be predicted.

The according work packages are:

  • Literature research
  • Implementation of the model framework
  • Implementation of phenomenological models for packed & sieve tray columns
  • Comparison between implemented model and literature data
  • Visualization of column operating points
  • Written elaboration

What you can gain:

  • Experience in most important liquid-liquid extraction phenomena
  • Experience in apparatus modelling
  • Experience in Python
  • Motivated supervision

Your profile:

  • Interest in liquid-liquid extraction
  • Structured and independent work ethic
  • Creativity in problem solving
  • Previous experience in simulation tools is advantageous

In case of interest, you are welcome to contact me with a short resume and your current sheet of records to make an appointment. The work can be written in German or English.

[1] Henschke, Martin (2004): Auslegung pulsierter Siebboden-Extraktionskolonnen
[2] Weber, Benedikt (2018): CFD-gestütztes Kompartiment-Modell für die Simulation von Flüssig/flüssig-Extraktionskolonnen
[3] Drumm, Christian (2010): One-Group Reduced Population Balance Model for CFD Simulation of a Pilot-Plant Extraction Column