PHYSICOCHEMICAL PROPERTIES OF BIODIESEL BLENDS DERIVED FROM MAHOGANY (KHAYA SENEGALENSIS) SEED OIL FOR USE AS ALTERNATIVE FUEL

Abstract

Plants from different regions produce oils with characteristics that vary by wide margins and depend more on the regions in which the plants are grown than the species from which the oils are derived, most probably as a result of the environmental conditions to which they are exposed. This study aims at producing biodiesel by transesterification of Khaya Senegalensis seed oil (KSO) and the determination of physicochemical properties of the biodiesel blends, compared with ASTM D6751 and EN14214 standards. Properties analyzed include: density, viscosity at 25⁰C, iodine value, saponification value, cloud point, pour point, flash point, acid value, free fatty acid, higher heating value and sulphur content. The transesterification reactions were maintained at the optimum process conditions of methanol/oil ratio 6:1, at 7⁰˚C for 60 minutes at 0.84% (w/v) of catalyst concentration. A biodiesel yield of 89.50% was obtained. The results for density (844 – 837 kg/m³), kinematic viscosity (4.44 – 4.07 mm²/s), iodine value (92 - 127 mgI₂/100g), saponification value (11.22 – 36.47 Mg/KOHg), cloud points (9 - 14 ᶱC), pour points (11 - 19 ^oC), flash points (110 - 190 ^oC), acid value (0.21 – 0.78 Mg/KOHg) and the sulphur contents (2.15 – 2.86 mg/kg) of the biodiesel blends (B10, B20, B30, B40, B50 and B100) conformed with both the ASTM D6751and EN14214 standard, with higher heating value of the blends slightly above both standards. It was concluded that with the high yield and quality properties of the biodiesel blends, the potential of using KSO biodiesel blends as an alternative fuel on a diesel engine.