Biodiesel – (FAME – fatty acids methyl esters) is currently produced through the esterification of free fatty acids and the transesterification of triglycerides in multi-stage reactors that are limited by mass transfer. The search for highly efficient transformation methods is therefore a key issue in context of minimizing reactor sizes and accelerating rates, in particular when processing non-edible and raw oils1,2. We evaluated the esterification rate of FFA to FAME over heterogeneous catalysts subject to either ultrasound (US) or microwaves (MW). Both US and MW remarkably accelerate the esterification reaction rates for temperatures below 313 K. In particular, at 293 K the FFA conversion triples when using US instead of conventionally stirred reactor. The use of MW is beneficial when associated with heterogeneous catalysts3 and contributes to increasing the oil-methanol solubility4. Process intensification of biodiesel production by transesterification with US horns in batch reactors (traditional vessels and Rosett cell reactors) and continuous flow reactors was studied. Complete conversion within 30 minutes was achieved for most of the US-assisted methods, whereas the mechanically stirred transesterification required two steps and lasted over 150 minutes, in between which the separation of the products was necessary. After only 5 minutes, biodiesel yields higher than 90 % were measured in the Rosett cell reactor, which combines hydrodynamic and acoustic cavitation, when US pulses were applied. The most significant result of this work was achieving biodiesel yields higher than 90% after just one passage of the reagents in the continuous flow reactor in the presence of pulsed ultrasound, corresponding to a reaction time of 18 seconds. In this case the reaction rate of the ultrasound-assisted process accelerated the reaction rate by 300 times versus the conventional synthesis methodology All the US horns used for the transesterification experiments were provided by Synetude (Chambery – France), including the continuous reactor Sonitube®. References 1Bianchi. C.L.; Pirola, C.; Boffito, D.C.; Di Fronzo, A.; Carvoli, G.; Barnabè, D.; Rispoli. A.; Bucchi, R. Non edible oils: raw materials for sustainable biodiesel. In Biodiesel Feedstocks and Processing Technologies; Stoytcheva, M. and Montero G., Eds.; Intech, 2011; p. 3. 2Boffito, D.C.; Pirola, C.; Galli, F.; Di Michele, A.; Bianchi, C.L. Free Fatty Acids Esterification of Waste Cooking Oil and its mixtures with Rapeseed Oil and Diesel. Fuel 2012, 10.1016/j.fuel.2012.10.069. 3Chemat, F.; Poux, M.; Galema, S.A. Esterification of stearic acid by isomeric forms of butanol in a microwave oven under homogeneous and heterogeneous reaction conditions. J. Chem. Soc., Perkin Trans. 1997, 2, 2371-2374. 4Patil, P.D.; Gude, V.G.; Mannarswamy, A.; Cooke, P.; Munson-McGee, S.; Nirmalakhandan, N.; Lammers, P.; Deng, S.G. Optimization of microwave-assisted transesterification of dry algal biomass using response surface methodology. Biores. Technol. 2011, 102, 1399-1405.
|Titolo:||Sonochemical Techniques for the Transformation of Bio-based oils into Fuel|
BOFFITO, DARIA CAMILLA (Secondo)
PIROLA, CARLO (Ultimo)
|Data di pubblicazione:||11-lug-2013|
|Settore Scientifico Disciplinare:||Settore CHIM/04 - Chimica Industriale|
|Citazione:||Sonochemical Techniques for the Transformation of Bio-based oils into Fuel / C.L.M. Bianchi, D.C. Boffito, J.-M. Leveque, G. Patience, C. Pirola. ((Intervento presentato al 1. convegno Asia-Oceania Sonochemical Society Meeting tenutosi a Melbourne nel 2013.|
|Appare nelle tipologie:||14 - Intervento a convegno non pubblicato|