(217c) Systematic Analysis of Cloud Point and Crystallization in Fatty Acid Ethyl Ester Biodiesel Mixtures

Saturated biodiesel components, fatty acid methyl esters (FAMEs) or fatty acid ethyl esters (FAEEs), crystallize at high temperatures, which limits their commercial application. FAEEs are particularly advantageous biodiesel components because they can be renewably sourced and have lower cloud points (CP) than FAMEs with the same carbon-chain length. This research systematically evaluates FAEE cloud point and crystallization data to aid in the development of FAEE biodiesel blends with practical cold flow properties. The effects of cold-flow improving additives dimethyl azelate (DMA) and triacetin (TA) on FAMEs and FAEEs are also analyzed. Neat FAEE CP increases with carbon-chain length and decreases with greater degree of unsaturation, and saturated/saturated FAEE mixtures show partial cocrystallization. Additives lowered the CP, but did so via different mechanisms. Thermodynamic ideal solution modeling accurately predicts binary FAEE CP with and without additives within 2% of experimental values.