Fuel properties of biodiesel from vegetable oils and oil mixtures. Influence of methyl esters distribution

• Biodiesel quality produced by basic transesterification from vegetable oils.
• We examine influences of methyl esters distribution on biodiesel properties.
• Biofuels from soybean, sunflower and rapeseed oils were with better properties.
• Oils mixtures improve biodiesel quality to fulfill Norm EN 14214.
• An equation to predict properties of biodiesel from oil mixtures is proposed.

In this work, the quality of biodiesel produced by basic transesterification from several vegetable oils (soybean, rapeseed, sunflower, high oleic sunflower, Cynara Cardunculus L., Brassica Carinata and Jatropha Curca) cultivated in Extremadura has been studied in detail. The influence of raw material composition on properties such as density, viscosity, cetane number, higher heating value, iodine and saponification values and cold filter plugging point has been verified. Other biodiesel properties such as acid value, water content and flash and combustion points were more dependent on characteristics of production process. Biodiesel produced by rapeseed, sunflower and high oleic sunflower oils transesterification have been biofuels with better properties according to Norm EN 14214. Finally, it has been tested that it is possible to use oils mixtures in biodiesel production in order to improve the biodiesel quality. In addition, with the same process conditions and knowing properties of biodiesel from pure oils; for biodiesel from oils mixtures, its methyl esters content, and therefore properties dependent this content can be predicted from a simple mathematical equation proposed in this work.