Mass Transfer Modeling of α-Eleostearic Acid from Tung Oil Concentration by Low-Temperature Crystallization

With the significant attention paid to alpha-eleostearic acid (alpha-ESA) in a variety of biologically beneficial effects, the demand for high-concentration products is increasing. A method of cryogenic separation to predict the mass variation of alpha-ESA from tung oil was established in this study. The results showed that the best alpha-ESA crystallization condition was -20 degrees C in ethanol, which implied a low energy consumption when compared with the common crystallization temperature of -60 degrees C. The alpha-ESA concentration in the liquid phase was reduced by 90.4% compared to tung oil, and most of the alpha-ESA in the solution was recovered by mass transfer. On the other hand, a mathematical model based on the diffusion reaction theory is used in mass variation prediction. The effects of temperature and time on the mass variation in alpha-ESA in solution crystallization were examined. The results showed that the proposed model could estimate the composition and total mass of winterized tung oil at R-2=0.974. The model was validated by experiments with an error of +/- 10%.