Characterization and evaluation of African bush mango Nut (Dika nut) (Irvingia gabonensis ) oil biodiesel as alternative fuel for diesel engines

Abstract

The African bush mangos (Irvingia gabonensis) were collected from the wild, dried and the kernels were split to release the nuts. The oil from the nuts was extracted in a soxhlet extractor that was operated at 60°C using normal hexane as solvent. It gave an oil content of 60% which was mainly triglyceride and was solid at room temperature. It was heated to 40°C to liquefy it and a methanol molar ratio of 6 to 1 was used along with 4 g/L of sodium hydroxide as catalyst during transesterification to biodiesel. Chromatography analysis of the biodiesel gave 59% linolenic fatty acid and tests show that the biodiesel has properties that are within the American society for tests and materials limits for biodiesel. Of particular significance is the cloud point of -14°C which allows it to be used in cold conditions and a flash point of 97°C that makes it a safe fuel during storage. The performance characteristic is similar to that of diesel fuel and the specific fuel consumption is 8% higher than diesel fuel which is consistent with the difference in their heating values. The oil will thus be a potential source of alternative fuel for diesel engine.  Key words: African bush mango (Irvingia gabonensis), fuel properties, biodiesel, transesterification.