Continuous production of biodiesel from rapeseed oil by ultrasonic assist transesterification in supercritical ethanol

• Published in: The Journal of supercritical fluids 2016-12, Vol.118, p.107-118
• Main Authors: Mazanov, Sergei V., Gabitova, Asiya R., Usmanov, Rustam A., Gumerov, Farid M., Labidi, Sana, Amar, Mounir Ben, Passarello, Jean-Philippe, Kanaev, Andrei, Volle, Fabien, Neindre, Bernard Le
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Biodiesel; Catalysis; Catalysts; Ethanol; Ethyl alcohol; Fatty acids ethyl esters (FAEE); Heterogeneous catalyst; Short range order; Supercritical ethanol; Transesterification
• ISSN: 0896-8446; 1872-8162
• DOI: 10.1016/j.supflu.2016.07.009

[Display omitted] ⿢High yield (97.45%) of ethyl esters are obtained by using ZnO/Al2O3 (5wt%) under SCF conditions (T=623K, P=30MPa, molar ratio ethanol/oil ⿿12:1).⿢A comparable yield (97.46%) obtained under the same conditions with the SrO/Al2O3 (2wt%) catalyst.⿢SrO/Al2O3 was found to be the best candidate for biodiesel production. In Europe, rapeseed is a renewable raw material which has been widely used for the production of biodiesel by various processes. The transesterification reaction of rapeseed oil with ethanol to biodiesel in supercritical fluid conditions was investigated using several heterogeneous catalysts and preliminary ultrasonic emulsification of the reaction mixture, to run the reaction at mild conditions. Phase equilibrium of fatty acids in supercritical ethanol was study to determine the operating condition in supercritical states. Transesterification experiments were carried out under a pressure of 30MPa, with ethanol to oil molar ratio (in the range of 12:1⿿20:1), temperature (623K to 653K), and the catalyst loading level and type were the main parameters. The most important characteristics of Al2O3 support catalyst and the impregnation method with aqueous solution of metal nitrates are also described. Yields of Fatty Acids Ethyl Ester (FAEE) are reported for different ZnO/Al2O3, MgO/Al2O3, SrO/Al2O3 catalysts in different experimental conditions. The higher yield of 97.46% was obtained under the optimal conditions 623K, 30MPa, 12:1 ethanol/FAEE molar ratio, with SrO/Al2O3 (2wt.% SrO) impregnated catalyst.