DETERMINATION OF THE PHYSIOCHEMICAL PROPERTIES OF DIESEL OIL COMMERCIALLY AVAILABLE IN BENIN CITY

This study assessed the physicochemical quality of diesel oil sold in Benin City, Edo State, Nigeria, using aggregate samples collected from four local government areas (Egor, Oredo, Ikpoba-Okha, and Ovia North-East). The scope covered five key parameters—flash point, distillation characteristics, density, basic sediment and water (BSW), and colour selected for their direct impact on safety, efficiency, and compliance with standards. Diesel samples were collected in sealed one-liter containers, combined into four aggregates, and analyzed using ASTM methods (D93 for flash point, D86 for distillation, D1298 for density, D1796 for BSW, and D1500 for color). Results showed distillation ranges within specification, with initial boiling points of 160–165 °C and final boiling points of 355–356 °C, and final recovered volumes of 97–98 mL, indicating uniform volatility. Density corrected to 15 °C ranged from 0.834 g/mL (Oredo) to 0.847 g/mL (Ovia North-East), aligning with the acceptable 0.82–0.85 g/mL range. BSW content was consistently low at 0.05%, while ASTM colour values ranged from 1.0 to 1.5, all within standards. However, flash points were below 52 °C across all LGAs, failing to meet the ASTM D975 minimum, suggesting contamination or blending with lighter fractions. The findings highlight generally consistent diesel quality but raise safety concerns requiring regulatory oversight.