Modelling and simulation of supercritical CO2 extraction of bioactive compounds from vegetable oil waste

Deodorizer distillates are waste by-product from vegetable oil industries. It has excellent potential as a source of bioactive compounds. Therefore, the aim of this study was to model the thermodynamic phase equilibrium and optimize the supercritical CO2 extraction processes for concentrating valuable minor components from rapeseed oil deodorizer distillates (RODD). The extraction was done in a countercurrent extraction column at pressure (35−40 MPa), temperature (313 K) and solvent to feed mass ratio (S/F) of 5. The raw material employed was initially saponified. Investigating the extraction process, representing phase equilibria behavior of the multicomponent oil-type material/CO2 mixture and prediction the steady-state efficiency of the extractor was done by using the Stryjek–Vera Peng–Robinson equation of state as a thermodynamic model for the experimental bubble pressures and vapor compositions. The extraction of β-sitosterol and vitamin E in the saponified RODD at predicted conditions showed a recovery of 76 wt% with a purity of 60 wt% and a recovery of 85 wt% with a purity of 75 wt% respectively. Furthermore, the use of a modified sample increased the phytosterol and tocopherol efficiency and purity. The absolute average relative deviation between the theoretical and experimental was within the range of 1–12%, which is considered as a good agreement. The coupling of thermodynamic modeling with experimental work offered an efficient and rapid tool for analyzing the viability of the supercritical extraction.