Biodiesel crystallization fractionation

Many approaches for improving the cold flow properties of biodiesel have been explored. These include blending with petrodiesel, transesterification with medium or branched-chain alcohols instead of methanol or ethanol, crystallization fractionation, and treatment with cold flow improver (CFI) additives. 

Palm oil methyl ester presents an onset of crystallization above 0 °C (i.e. 6 °C) and a steep crystallization slope (Fig. 13.3a). Thus, its cold flow properties will be poorer than those of the rapeseed methyl ester. The crystallized fractions (CFs) determined at -15 °C for MEl, ME2 and DF are 2.3,1.5 and 25.9%, respectively. These percentages were calculated using the enthalpy of crystallization of DF (210 J/g) obtained elsewhere [9]. The same linear relation obtained for diesel fuels has been used for biodiesel and biodiesel blends ... 

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