Supercritical extraction of sunflower seed oil: Experimental data and model validation

In this work experimental results of sunflower seed oil extraction using supercritical CO₂ are presented, together with the outcome obtained by applying to the same data a theoretical model recently developed and further improved here.We performed extraction tests utilizing a supercritical extraction equipment having a volumetric capability of 100 ml; the seeds were milled to obtain different particle sizes (mean diameter between 0.19 and 1.2 mm); the range of pressure investigated was 280–550 bar, the temperature and solvent flow rate were maintained constant at about 40 °C and 10 g/min, respectively.The model accounts for the distinction between broken and intact oil-bearing cells and describes the extraction kinetics similar to the shrinking core models: it allowed satisfactory fitting of the experimental data and permitted to calculate the effective diffusivity of the oil in the seed, which resulted equal to 3 × 10⁻¹¹ m²/s. The reliability of the model is demonstrated by the fact that the value of the effective diffusivity, resulting from model optimization procedures, is similar for the various experimental tests.