This graph displays the iodine values and acid values of the Jatropha oil, before and after it was heated at 70oC for 45 minutes. The overall trend of the data is that the oxidation stability of the oil decreases when it is exposed to high temperatures and oxygen. The iodine value increased by over 30% and the acid value increased by a little less than 70% when the heat was increased. This indicates that high temperatures and exposure to oxygen increase the unsaturation of Jatropha oil and make it more susceptible to attacks from free fatty acids, and thus, decreasing the oxidation stability of the Jatropha oil.
This graph displays the iodine values and the acid values of solutions
containing different proportions of TBHQ after the oil solutions had been
exposed to oxygen and heat. The fact that the acid value decreased as more of
the antioxidant was added means that the antioxidant had successfully protected
the fuel from further free fatty acid attacks and eliminated existing free fatty
acids. The TBHQ showed great success in decreasing the unsaturation level of the
oil. In comparison to the 100% Jatropha oil, the solution with 1.0mL of TBHQ
decreased the iodine value by almost 50%. This means that with 10% antioxidant,
the oil’s susceptibility to free fatty acids and oxygen was significantly
decreased and therefore, the TBHQ had improved the oxidation stability of
Jatropha Oil.
This graph displays the iodine values and the acid values of solutions
containing different proportions of IRGASTAB BD 100 and Jatropha Oil. Just as
with the TBHQ solutions, the IRGASTAB BD 100 solutions showed great improvements
with the iodine value. The solution containing 10% of the additive decreased the
iodine value by 65%. The solution containing 5% of the additive saw a more
modest improvement of a little over 50%. The solutions containing IRGASTAB BD
100 significantly decreased the unsaturation levels of Jatropha Oil. The
solutions containing IRGASTAB BD 100 also affected the acid value. The solution
with the highest concentration of additive caused the acid value of Jatropha oil
to decrease by almost 50%. This means that the additive not only prevented the
oil from further degradation from free fatty acids, but also eliminated a lot of
the existing free fatty acids. Therefore, the solutions containing IRGASTAB BD
100 were highly successful in improving the oxidation stability of Jatropha Oil.