(64f) Roles of Urea Inclusion Fractionation of Biodiesel on the Cold Flow Properties and Establishment of Feedstocks for Biochemicals and Biomaterials

Biodiesel mainly consists of methyl esters derivatives of long-chain fatty acids and is viewed as the renewable alternative to petroleum diesel for carbon sequestration and mitigating environmental problems. However, its utilization is constrained by the poor cold flow properties. Cloud point, the onset temperature of thermal crystallization, can appropriately evaluate cold flow properties. The saturated components with high melting points significantly influence cloud points, and removing saturated components can effectively reduce the cloud point. Distillation, solvent thermal extraction, and thermal crystallization are the fractionation based on the phase equilibrium and own the disadvantages of low yields and slow production rate. A particular method was performed to fractionate FAME at room range temperatures by forming solid urea inclusion compounds (UIC). Urea inclusion fractionation provides a way to reduce the cloud point of mixtures of FAME by preferentially removing high melting-point linear saturated FAME components. Since soybean oil is the primary feedstock for biodiesel in the United States, the effects of the mass ratio of urea to FAMEs, the mass ratio of methanol to FAMEs, and the type of solvents on urea inclusion fractionation were carried out on FAMEs from soybean oil in urea inclusion fractionation. In addition, FAMEs from other sources were used to test the feasibility of urea inclusion fractionation on the cold flow properties. According to the experiments, the cloud point of biodiesel from soybean oil after urea fractionation could be as low as -52 ^oC. After twice urea inclusion fractionation for palm oil biodiesel, the cloud point can reach as low as -17 ^oC. In addition, the effect of urea inclusion on the biodiesel was also evaluated in the cetane number, oxidation stability, nitrogen oxides emission, etc. The separation efficiency and selectivity were measured according to the driving force in urea inclusion fractionation. Compared to distillation solvent thermal extraction and thermal fractionation, urea inclusion fractionation could reach high yields and good cold flow properties.