Potential of Mafura seed oil as a feedstock for biodiesel production

Abstract

Environmental concerns caused by the constant use of fossil fuels can be solved by the use of biofuels. This work shows the application of the oil of Trichilia emetica Vahl (Mafura) seeds originating from Mozambique as a feedstock for biodiesel production. The high oil acidity required a two-step reaction involving esterification using sulphuric acid (H2SO4) as catalyst followed by for the conversion of Mafura oil to fatty acid methyl ester (FAME). The acid value was reduced from 27.58 to 0.36 (mg KOH g −1). Other physicochemical properties (moisture content, density, free glycerol) of FAME attended the established limits of EN14214 and Brazilian norms. The low induction-period (IP) was surpassed after the addition of 500 ppm of the synthetic antioxidant tert-butylhydroquinone (TBHQ) resulting in 10.8 h. The conversion of the feedstock (99.1%wt) was confirmed by gas chromatograph with flame ionization detector (GC-FID). The fatty-acid methyl ester contents of the Mafura biodiesel presented palmitic acid (39.32%wt), linoleic acid (31.09%wt), oleic acid (25.77%wt), stearic acid (2.29%wt), meristic acid (0.78%wt), linolenic acid (0.61%wt) and lauric acid (0.14%wt). These results show that the biodiesel produced from Mafura oil met most of the quality standards required by American, Brazilian and European regulatory agencies.