Separations Technology

Traditional separation processes like distillation have been around for centuries. However, the underlying fundamentals of these processes are in many cases still not fully understood. The Separations Technology research group focusses on understanding the underlying fundamentals of thermal separation processes, and investigating alternative processes and technologies applicable to the separation of hydrocarbon mixtures.

Processes include traditional separation techniques such as distillation, absorption, adsorption and liquid-liquid extraction but also include advanced processes such as membrane separation and supercritical fluid fractionation. The research group focusses, in part, on the separation of compounds where the underlying systems may exhibit azeotropy and association due to hydrogen bonding, and the systems may involve molecules with varying polarity and asymmetrical structure. Here the aim is to understand how the structure of a molecule affects its macroscopic behaviour. The research group also focusses on characterising separation column internals based on hydrodynamic and mass transfer behaviour. The characterisation of absorption, adsorption, distillation as well as supercritical fractionation applications are all included in this focus area.

Our main research thrusts are currently:

  • High/supercritical and low pressure phase equilibria measurement (VLE, LLE and VLLE)
  • Thermophysical property measurement (density, speed of sound)
  • Thermodynamic and process modelling
  • Hydrodynamic characterisation of tray and packed columns
  • Mass transfer characterisation of packed columns
  • Supercritical fluid extraction and/or fractionation of high molecular mass compounds
  • Hydrodynamic characterisation of packed supercritical fractionation columns
  • Adsorption for product purification of hydrocarbon streams and for cleaning waste streams
  • Membrane technology for membrane distillation and organic solvent nanofiltration (OSN).

The separations technology research group has a number of state of the art setups, including:

  • High pressure static-analytic and static-synthetic phase equilibria units
  • Low pressure vapour-liquid-liquid equilibrium stills
  • Adsorption kinetics and equilibrium characterisation units
  • Wetted Wall
  • Absorber and stripping columns for mass transfer characterisation and CO2 sequestration
  • Hydrodynamic characterisation pilot plants
  • Supercritical fluid fractionation and extraction pilot plants

These set-ups are supported by modern analytical equipment:

  • Gas chromatography with online analysis capability
  • Liquid surface tension and density meter
  • Compressed liquid density and sound velocity meter
  • Fourier Transform Infrared (FTIR) and Ultraviolet-visible (UV-viz) spectrometers
  • Other required analyses performed by the Department Process Engineering’s state of the art in-house analytical facilities.

The researchers listed below all form part of the Separations Technology group. Follow the link to their individual profiles to find out more about their research interests and activities.

Prof André Burger
Departmental Chairman | Professor
Dr LJ du Preez
Lecturer
Ms Sunel Nortjé
Lecturer
Prof Cara Schwarz
Professor