Biodiesel Production from Rubber Seed: In-situ Transesterification
Due to the increase in crude price oil prices and environmental concerns, a search for sustainable alternative fuel has gained significant attention. Use of non-edible feedstock in biodiesel production such as rubber seed would reduce the feedstock cost and biodiesel can remain competitive to petroleum diesel. A combined process of oil extraction and reaction, named in-situ transesterification, would further reduce the processing step and hence the production cost. However, rubber seeds contained high free fatty acid (FFA) and therefore double treatment (acidic and alkaline treatment) was introduced.
A series of lab scale experiments were carried out by grinding the rubber seed into smaller flakes, performing in-situ transesterification using water bath at temperature of 60 oC, filtrating the seeds and finally purifying the product. The experiment was repeated using different time study of 1,2,4 and 6 hours. The variables analysed were ratio of solvent to alcohol, types of alcohol, ratio of alcohol to seeds, type and strength of catalysts and effect of single and double treatment. Thin Layer Chromatography (TLC) analysis was carried out to give a quick and reliable result.
For the first treatment, in-situ acidic esterification was carried out. A combination of 1 wt% of sulphuric acid and 100 ml of ethanol without presence of the solvent, yielded the highest amount of biodiesel of about 50 wt%. In the second treatment, the combination of 1 wt% of Sodium Hydroxide and 100 ml of methanol yielded 83 wt% of biodiesel. Both treatments reached optimal condition at 2 hours time study.