High-quality biodiesel starts with high-quality feedstock. To meet international standards such as EN 14214 (EU) or ASTM D6751 (US), biodiesel must comply with strict chemical and physical parameters that ultimately trace back to the composition of the oils or fats used in production.
Let’s explore four critical parameters that shape both biodiesel quality and the selection of feedstocks:
- Oil / Fats Content
The foundational component of biodiesel is oil or fat—ideally with minimal contaminants and high conversion efficiency. Feedstocks with high levels of mono-, di-, and triglycerides are preferred, as these directly influence the FAME (fatty acid methyl ester) yield and purity. Unconverted fats or partial glycerides in the final product can cause injector fouling, filter blockages, and poor cold performance. - Iodine Value (IV)
The iodine value indicates the degree of unsaturation in fatty acids. A higher IV means more double bonds, which makes the biodiesel more prone to oxidation and less stable during storage. The EN 14214 standard limits IV to 120 g Iodine/100 g of biodiesel. Feedstocks like palm or animal fats generally have low IV, offering higher oxidative stability, while oils like soybean or sunflower may exceed this threshold unless blended or stabilized. - Phosphorus Content
Phosphorus, usually present in crude vegetable oils as phospholipids or introduced during processing, is a known poison for catalytic converters and particulate filters. Even in trace amounts, it can cause long-term issues in emission control systems. The EN 14214 limit is 4 mg/kg, making degumming and post-treatment of feedstock essential, especially when using crude or recycled oils. - Sulphur Content
Sulphur compounds can originate from plant uptake or protein residues in animal fats. While vegetable oils usually contain 2–7 mg/kg of sulphur, animal fats may exceed 30 mg/kg and require additional refining. EU fuel regulations cap sulphur content at 10 mg/kg, underscoring the need for careful sulphur monitoring in biodiesel production.
In summary, biodiesel quality is only as good as the feedstock behind it. By controlling input parameters like fat purity, iodine value, phosphorus, and sulphur content, producers can ensure that the resulting biodiesel meets international performance and environmental standards.
If you’re sourcing raw materials for biodiesel production, contact Prime Elements — we provide traceable, quality-verified feedstocks tailored to your process and market requirements.
