Phase Equilibria of Highly Asymmetric Mixtures Involved in Biodiesel Production

Abstract

In recent years, hydroconversion of vegetable oils has been considered a promising route for biodiesel production. The process involves highly asymmetric mixtures of hydrocarbons and triglycerides which exhibit complex phase behaviours. In this work, thermodynamic modelling of C3-C16 and C3-triglyceride mixtures was performed by means of Peng-Robinson and PC-SAFT EOS. Critical properties and PC- SAFT parameters for triglycerides were estimated with group contribution methods; furthermore, an approach for evaluation of triglyceride PC-SAFT parameters, based on regression of experimental binary phase equilibrium data, was proposed. The PC-SAFT model showed its capacity to depict chain molecule phase behaviour providing better predictions for all the system investigated and it is recommended as reference EOS to represent phase equilibria involved in vegetable oils hydroconversion process.