Mass transfer modeling of Scenedesmus sp. lipids extracted by supercritical CO2

According to the external mass transfer coefficient, mass transfer correlations were developed to relate Sherwood number to Reynolds, Schmidt, and Grashof numbers. It was found that when Schmidt exponent was fixed at 1/3 (model 1), the model did not fit the experimental data well, whereas when the power was adjusted and considered as a fitting parameter the coefficients of determination increased significantly exceeding 90%. The natural convection effect was found to be insignificant compared to the forced convection. The validity of the developed correlations with coefficients determined from experimental data collected from a small scale extraction cell was confirmed by predicting the overall extraction curve (OEC's) of a larger scale extraction cell.