Modelling of the phase behaviour for vegetable oils at supercritical conditions

This work describes a generalized procedure for high pressure equilibrium calculations for vegetable oils. The present approach considers any vegetable oil as composed by two key components: oleic acid (OA) and triolein (TO). OA is representing the low molecular weight compounds, those related with acid value and the products of degradation. TO refers the fatty content. The mathematical procedure used commercial ASPEN-plus (R) software package to process CO2-OA-TO equilibrium data according to the classical cubic equations of state (EOS). The theoretical data calculated by the package fit fairly well with the experimental results published for a wide variety of vegetable oils, especially for seed extracts. Equilibrium calculation theoretical results were in good agreement with literature data for acid value and also confirmed than can be used to predict properly continuous countercurrent processes. The model proposed in this work can be useful for preliminary scale-up and economical evaluations avoiding specific equilibrium data determination, with special interest in deacidification processes. (C) 2008 Elsevier B.V. All rights reserved.