Flow and crystallization of saturated fatty acid methyl esters and their binary mixtures

• Published in: Journal of the American Oil Chemists' Society Vol. 99; no. 7; pp. 613 - 619
• Main Authors: Helsper, Sedi, Hatem, Wesam A., Young, Lisa, Wilhelm, Zane, Liberatore, Matthew W.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.07.2022
• Subjects: biodiesel; fat crystallization; fats and oils; rheology
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1002/aocs.12598

Demand for biodiesel has increased due to being a more environmentally‐friendly fuel. Cold weather operation of biodiesel is challenging due to fatty acid methyl ester (FAME) content in biodiesel. Saturated FAMEs crystallize at relatively high temperatures, increase the viscosity of biodiesel, and can clog fuel lines. Here, several factors altered crystallization temperature (CT) of FAMEs, including composition, shear rate, and cooling rate. The crystallization of pure and binary mixtures of methyl palmitate, methyl myristate, and methyl stearate were studied under shear flow and static conditions. Static phase CTs of pure methyl palmitate, methyl myristate, and methyl stearate were 26, 14, and 35°C, respectively. In binary mixtures, CTs were depressed up to 7°C, which agreed with freezing point depression theory. Increasing shear rate up to 100 s−1 decreased CT by 2°C compared to static conditions. Decreasing cooling rate from 1 to 0.1°C/min increased CT less than 2°C. Overall, FAME composition altered CT more than shear flow or cooling rate for pure and binary mixtures of three FAMEs.