Abstract:
Global energy crises and environmental concerns arising from oil spillage and exhaust
gaseous emissions into the atmosphere are the major problems of fossil fuel use. Due to
the environmental problems caused by using fossil fuels, considerable attention has been
made to biodiesel production as an alternative to petro-diesel. Biodiesel is an ecofriendly,
alternative diesel fuel prepared from renewable resources i.e. vegetable oils and animal
fats. It is a renewable source of energy that can be an ideal solution for global energy
demands including Ethiopia. The objective of this study was to investigate the production
of biodiesel from blends of crude castor oil and microalgae using methanol with KOH
(Potassium hydroxide) as a catalyst. Optimum molar ratio of alcohol to oil, volumetric
ratio of castor oil to microalgae oil and catalyst concentration was investigated during
experimental process. Transesterification process was used to produce biodisiel from oil
with methanol in the presence of base catalyst. The oil was extracted by Solvent
extraction method, using n-hexane as the solvent from both algae and castor seeds
powder separately, and then it was mixed together. Biodiesel was produced through
blending of algae and castor oil using methanol in the presence of potassium hydroxide
as catalyst at the end of the reaction glycerol and biodiesel were form two layers. After
settling, the glycerol layer was at the bottom while the biodiesel layer was at the top of
the container. The layers were later separated from each other by draining the glycerol
from the bottom of the flask containing the mixture. The biodiesel was washed several
time to remove the remaining glycerol and stored properly. Optimum parameters for the
production of biodiesel such as molar ratio of methanol to oil, volumetric ratio of castor
oil to algae oil and catalyst concentration were investigated. The optimum parameters
obtained were molar ratio of methanol to oil, volumetric ratio of castor oil to algae oil
and catalyst concentration of 9:1(v/v), 2:1(v/v) and 1.5% (wt/wt) respectively. From
optimum parameter the optimum biodiesel yield was 86% (v/v). The yield obtained was
nearly similar with the predicted yield by the software (RSM). Finally fuel properties of
the biodiesel were tested.
