Abstract

Alternative fuel is currently an important issue all over the world due to the efforts on reducing global warming which is contributed by the combustion of petroleum or petrol diesel. Biodiesel is non-toxic, biodegradable, produced from renewable sources and contributes a minimal amount of net green house gases, such asCO₂, SO₂ and NO emissions to the atmosphere. The study was carried out to produce biodiesel from waste/recycled oils to reduce the cost of biodiesel, waste and pollution. Some important variables such as volumetric ratio, types of reactants and catalytic activities were selected to obtain a high quality biodiesel fuel within the specifications of the American Standard for Biodiesel Testing Method (ASTM D 6751) and European Norm (EN 14214). The highest biodiesel yield was obtained (71.2%) under the conditions of 1:1 volumetric oil-to-methanol weight ratio, 0.5% NaOH catalyst at 50°C reaction temperature and 320 rpm stirring speed. The results showed that biodiesel produced from different oil to methanol ratios, alcohol types and shaking time exhibited considerable differences. There was also a considerable difference of biodiesel yield produced by using methanol, ethanol and 1-butanol. The biodiesel yield increased in the order of 1-butanol < ethanol <methanol. There was a little difference in viscosity, acid value and chemical elements (Fe, Mg, Ca, Na, P etc.) at different parameters. The research showed that biodiesel obtained under optimum conditions from completely waste oil was of good quality and could be used as a diesel fuel which is considered as potential use of waste cooking oil. In addition, bioenergy could be renewed and environmental recycling process could be maintained potentially using waste soybean cooking oil.

Key words: Waste soybean oil, biodiesel, viscosity, acid value, element content.

Abbreviation

TAN, Total acid number; FFAs, free fatty acids; FAME, fatty acid methyl esters.