Assessment of Thermophysical Properties of Selected Biofuel Blends for Application in Nigerian Stationary Engines

The blending of locally produced biofuels with conventional petroleum fuels offers a practical pathway to reducing fuel import dependence and lowering greenhouse gas emissions in Nigeria's distributed energy sector. This study assesses the thermophysical properties of binary blends of palm oil biodiesel and diesel fuel at blending ratios of B10, B20, B30, and B50 by volume, prepared from crude palm oil feedstock sourced from processing mills in Imo State, South East Nigeria. Properties measured include density, kinematic viscosity, flash point, calorific value, cetane index, cloud point, and pour point following ASTM standard testing protocols. Measurements were conducted at temperatures of 15, 25, and 40 degrees Celsius to characterize temperature dependence. Results indicate that density and viscosity increase monotonically with biodiesel content, with B50 exhibiting kinematic viscosity of 5.8 mm2/s at 40 degrees Celsius compared to 3.1 mm2/s for neat diesel. Calorific value decreases approximately proportionally with biodiesel fraction, with B50 yielding 40.1 MJ/kg compared to 43.5 MJ/kg for diesel. Flash point increases with biodiesel content, improving storage safety characteristics. The study estimates engine fuel consumption adjustment factors required to maintain rated power output when transitioning from diesel to biodiesel blends in 10 kVA to 100 kVA stationary generator sets common in Nigerian commercial premises. Professional recommendations address optimal blending ratios for tropical climate operation, filter maintenance intervals, and biodiesel supply chain requirements. Keywords: biodiesel, thermophysical properties, palm oil, biofuel blends, stationary engines