ABSTRACT
The shipping industry’s use of biofuel blends has increased, with approximately 0.7% of the bunker fuel industry utilizing these blends (biodiesel or renewable diesel mixed with residual fuel or distillate) in 2023. One of the potential issues related to biodiesel blends is corrosion and oxidation stability.
Biodiesel’s water content can increase during storage, worsening its corrosive properties by promoting oxidation and acid formation, which can damage metal components in the fuel system and increase maintenance/replacement requirements.
Organic acids, formed through biodiesel oxidation due to dissolved oxygen during long-term storage, contribute to its corrosivity. Oxidation instability leads to oxidative products such as insoluble, gum, aldehydes, and alcohols, which can cause filter clogging, injector fouling, and deposit formation in the combustion chamber.
In this study, biodiesel blended with distillate fuels underwent accelerated aging following ASTM D4625 methodology (storage at 43°C, open to air, up to twelve weeks). Biodiesel blended with residual fuels was subjected to an in-house accelerated aging method (storage at 60°C, up to twelve weeks). A comprehensive analysis evaluates physicochemical properties, including acid number, sediment content, water, and free fatty acid/glycerin content. Additionally, we studied the impact of water on the storage properties of these biofuel blends.
In addition, this experimental work investigates the corrosiveness of biodiesels in the presence of steel rods at different immersion temperatures. The impact of water at various concentrations was also studied. Oxidation stability and chemical composition of biofuel blends were evaluated to identify any
correlations between these parameters and the corrosivity of the fuels.
The investigation will offer valuable insights into the stability, quality, and potential improvements of biodiesel blends with distillate and residual fuels. These findings will aid in informed decision-making regarding fuel formulation, quality control and management practices.