Impact of Antioxidant Additives on the Oxidation Stability of Diesel/Biodiesel Blends†

This study investigates the impact of various synthetic phenolic antioxidant additives on the oxidation stability of several neat biodiesels, with special emphasis on the stability behavior of diesel/biodiesel blends with the employment of the modified Rancimat method (EN 15751). The performance of antioxidants was evaluated for treating five biodiesels, obtained from different origins, and their blends with a typical automotive ultra-low sulfur diesel. The examined blends were in proportions of 2, 3, 4, 5, 7, and 10% by volume, similar to those that currently penetrate the European fuel market. All biodiesel samples were treated with a constant concentration of 1000 mg/kg of each additive and then blended with diesel fuel. The experimental results revealed that an improvement in oxidation stability could be achieved with all antioxidants tested, while the efficiency of the antioxidants varied depending upon the different types and quality of biodiesel. Among the antioxidants evaluated, butylated hydroxyt...