Impacts of alcohol type, ratio and stirring time on the biodiesel production from waste canola oil

The use of alternative fuels in order to reduce the environmental impacts of diesel emissions has been extensively investigated. Trends in the regional use of biomass-derived fuels, such as alcohols, biodiesel and agricultural residues as a proposed control initiative against elevated carbon monoxide levels in urban areas have expanded to a global scale. Waste cooking oil is considered as the most suitable material due to its readily-availability and cost-effectiveness. In this study, the transesterification of waste canola cooking oil was carried out using lower alcohol to oil molar ratios to study its feasibility. Some important variables such as volumetric ratio, types of reactants and shaking time were selected to obtain a high quality biodiesel fuel with the specification of American Standard for Biodiesel Testing Material (ASTM D 6751) and European Norm (EN 14214). The highest biodiesel yield was obtained (49.5%) under conditions of 1:1 volumetric oil-to-methanol weight ratio, 0.5% NaOH catalyst at 55°C reaction temperature and 250 rpm stirring speed. The results showed that biodiesel production from different oil to methanol ratio, alcohol types and shaking time exhibited considerable differences. There was also a considerable difference of biodiesel yield produced by methanol, ethanol and 1-butanol. The biodiesel yield increased in the order of 1-butanol < ethanol <methanol. There was little difference in viscosity, acid value and chemical elements (Fe, Mg, Ca, Na, P etc.) at different parameters. The result showed that the optimal combination which could give highest production of biodiesel was transesterification, carried out for 2 h by using methanol to oil molar ratio of 1:1, catalyzed by 0.5% sodium hydroxide and produced biodiesel can be used as fuel in diesel engine.