Nucleation Mechanism of Biodiesel Derived from Palm Oil at Low Temperatures

The compositions and crystallization process at low temperature of palm-based biodiesel (PME) are investigated. In this work, we show that PME is mainly composed of fatty acid methyl esters of 14-24 even-numbered C atoms: C14:0-C24:0, C16:1-C22:1, C18:2, and C18:3. Palm-based biodiesel crystallization comprises three steps, viz., forming supersaturated solution, nucleation and ester crystal growth; the driving force for saturated fatty acid methyl esters nucleation is the degree of supersaturation. The rate equation of nucleation is put forward. The objective of this research is to provide theoretical support for hindering the ester crystal nucleation and growth, and improving the cold flow properties of PME.