Abstract:

Jatropha curcas Linn has been identified worldwide as one of the sources of biodiesel. Biodiesel
has energy properties close to fossil diesel and can be a potential energy alternative. However,
these properties may vary based on soils, plant genetics and agro-climatic conditions in a given
geographical location. Several studies on biodiesel production under such conditions have been
done elsewhere, but few have been done on J. curcas oil in Uganda. This study analysed the physicochemical
properties of J. curcas L. oil for biodiesel production in Nebbi and Mukono districts
using American Standards and Testing Methods (ASTM D6751) and European Standards (EN
14214). J. curcas seed kernel contained 51% w/w and 48% w/w of oil with high levels of Free Fatty
Acids (1.52% and 1.93%) and acid values (35 and 36 mg KOH/g) for Nebbi and Mukono, respectively;
the difference was significant (p = 0.05). Generally, the quality and quantity of the oil from
Nebbi were better than those of Mukono, based on the biodiesel standard values. Nevertheless,
kinematic viscosity, acidity, potassium and phosphorus content values were found abnormally
high (31.46 - 33.23 mm2/s, 35.23 - 36.66 mg KOH/g, 16.50 - 20.52 mg/100g and 16.13 - 26.02
mg/kg, respectively) for both regions as compared to the standard values (3.5 - 5.0 mm2/s, 2 mg
KOH/g, <5 mg/100g and <10 mg/kg, respectively) of biodiesel for diesel engine. Such properties
are very important for engine fuels and if not considered well, may affect engine performance negatively.
Therefore adequate treatment of the oil by degumming, etherification and transesterification
before use in a diesel engine could avert this difficulty.