Physico and Thermo-chemical Characterization of Oil, Biodiesel and Biomass Derived from Moringa peregrina Seeds

Abstract

In this study, M. peregrina seeds were investigated, for the first time, as a potential source for biofuel. The seeds were obtained from Wadi Alkasinger in the Northern State of Sudan. Physical characterization revealed that, M. peregrina seeds are composed of 59% kernel and 41% husk. The kernel was found to contain about 38% oil. Higher heating values of 18.21, 20.65 and 39.99 MJ/Kg were obtained for M. peregrina seed husk, seed cake and seed oil, respectively. Thermochemical characteristics and the thermal behavior of M. peregrina seed husk and seed cake, in an inert atmosphere of N2 ,were studied. The results showed that, M. peregrina seed husk and seed cake could potentially produce energy through thermochemical conversion processes. Iodine value (67.73 g I2/100g oil) and saponification value (187.53 mg KOH/g oil) were observed for M. peregrina seed oil. Thus, a high cetane number (60.16) was calculated for M. peregrina seed-oil-based biodiesel. M. peregrina seed oil was found to contain very low amount of free fatty acids (0.35%), rendering its conversion into biodiesel possible in one step by alkaline catalyst. A high fraction of unsaturated fatty acids was observed in M. peregrina seed oil (81.24%), 76.92% of this fraction was monounsaturated fatty acids with oleic acid as the major component (72.19%). Therefore, high thermo-oxidative stability was observed in M. peregrina seed oil. The long chain fatty esters (C20:0 + C20:1+ C22:0) comprised about 6.76% of the oil. Biodiesel was produced by the transesterification reaction, catalyzed by potassium hydroxide. A high yield of biodiesel (97.79%) was obtained. M. peregrina biodiesel exhibited high oxidative stability (24.48 h). Moreover, the major fuel properties of M. peregrina biodiesel conformed to the ASTM D 6751 standards. However, kinematic viscosity (4.6758 mm2/s), density (876.20 Kg/m3), and flash point (156.5 C) were found higher than that of the diesel fuel. In addition, the calorific value of M. peregrina biodiesel (40.119 MJ/Kg) was lower than the diesel fuel. Besides, cloud point (15C), pour point (11C) and cold filter plugging point (13C) were ,relatively, high. The fuel properties of M. peregrina biodiesel were enhanced significantly by blending with diesel fuel. A blend contained up to 20% biodiesel, was found to have fuel properties very close to the diesel fuel.