abstract
Blending biodiesels is a well-established approach for the lowering of cloud and pour points. The use of ethylic biodiesel, with better cold weather properties due to the lower melting points of ethylic esters, could be another interesting alternative, promoting the utilization of more saturated oils and fats. To study that possibility this work evaluated the melting behavior of 3 mixtures of esters composed of ethyl palmitate, ethyl stearate or ethyl oleate with methyl palmitate. These esters are based on some of the most abundant fatty acids present on soybean and palm oils, two of the most expressive vegetable oils sources for biodiesel production. The solid-liquid phase diagrams in the entire concentration range of these 3 systems were evaluated with all phase transitions reported. The systems composed of saturated ethyl/methyl esters showed a very complex behavior, with the formation of solid solutions (organic alloys), peritectic reactions, and metatectic transitions. The liquidus lines of these systems were compared with the equivalent mixtures based on methyl esters alone showing that lower melting temperatures were achieved. Therefore blends between ethyl esters and methyl esters are suggested to improve the low temperature behavior of biodiesels.
keywords
SOLID-LIQUID EQUILIBRIUM; PHASE-DIAGRAMS; BINARY-MIXTURES; FATTY
subject category
Energy & Fuels; Engineering
authors
Maximo, GJ; Magalhaes, AMS; Goncalves, MM; Esperanca, ES; Costa, MC; Meirelles, AJA; Coutinho, JAP
our authors
acknowledgements
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID /CTM /50011/ 2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. The authors acknowledge the Brazilian funding agencies CNPq (305870/2014-9, 406963/2016-9), FAPESP (2014/21252-0, 2016/08566-1, 2012/05027-1), FAEPEX/UNICAMP (0125/16) and CAPES for financial support and scholarships.