Thermodynamic Modeling of Multi-phase Solid–Liquid Equilibria in Industrial-Grade Oils and Fats

Jeppe Lindegaard Hjorth, Rasmus L. Miller, John M. Woodley, Søren Kiil

Research output: Contribution to journalJournal articleResearchpeer-review


Compositional thermodynamic phase separation is investigated for industrial-grade vegetable oils with complex compositions. Solid–liquid equilibria have been calculated by utilizing the Margules 2-suffix activity-coefficient model in combination with minimization of the Gibb’s free energy of the system. On the basis of quasi-equilibrium solid-fat content (SFC) measurements, a new approach to the estimation of the interaction parameters, needed for the activity-coefficient model, has been developed. The parameters are fitted by matching the SFC of two oils at various degrees of dilution and isothermal temperatures. Subsequently, the parameters are successfully validated against three oils, rich in asymmetric and symmetric triacylglycerols (TAG), respectively. The new approach developed is shown to be very flexible, allowing incorporation of additional TAG and polymorphic states. It thereby provides a simple way to dealing with multi-component, multi-phase TAG mixtures without having the required binary interaction parameters at hand a priori. This ultimately provides a powerful, predictive tool which may serve as a starting point for laboratory screening and creation of tailor-made products because many different oil mixtures can be evaluated quickly with respect to specific properties, prior to more time-consuming experimental evaluation.
Original languageEnglish
JournalJournal of the American Oil Chemists' Society
Pages (from-to)17–28
Publication statusPublished - 2015


  • Activity coefficients
  • Interaction parameters
  • Mathematical modeling
  • Multi phase
  • Solid-fat content (SFC)
  • Solid–liquid equilibrium (SLE)
  • Triacylglycerols (TAG)
  • Vegetable oil
  • Binary mixtures
  • Free energy
  • Glycerol
  • Mathematical models
  • Oil shale
  • Phase equilibria
  • Phase separation
  • Vegetable oils
  • Liquid equilibria
  • Solid-fat contents
  • Triacylglycerols
  • Liquids

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