Study of the oxidation process in marine diesel blended with biodiesel and HVO

The adoption of biofuels in the maritime sector remains limited despite their environmental advantages, largely due to operational concerns associated with storage stability under high-humidity conditions typical of shipboard environments. This study investigates the oxidative and physicochemical stability of marine gas oil (MGO) blended with 30% (v/v) biodiesel (B30) or hydrotreated vegetable oil (HVO) (H30), focusing on miscibility and performance under two aging protocols: accelerated aging in a thermostatic oven and natural aging aboard a naval vessel, following the ASTM D4625 methodology. Analytical determinations included specific gravity, kinematic viscosity at 40°C, filter-blocking tendency (FBT), water content by Karl Fischer titration, and oxidative stability assessed by the RapidOxy method. B30 samples exhibited increased viscosity and FBT after both aging conditions, along with elevated water uptake, indicating significant degradation and higher hygroscopicity. In contrast, H30 maintained physicochemical parameters within or above MGO specifications, showing enhanced oxidative resistance and lower filterability loss. The results demonstrate that HVO-blended marine fuels exhibit greater long-term stability compared to biodiesel blends, supporting their application as drop-in alternatives for marine propulsion systems. These findings contribute to the growing body of evidence favoring the integration of HVO into maritime fuel matrices to advance decarbonization strategies while ensuring operational reliability and compliance with fuel performance standards.