Effect of Hydroxylated Compounds on Properties and Emission of Palm Biodiesel

The Malaysian Palm Oil Board (MPOB) attempted the search for a viable alternative fuel leading to a possible substitution to the conventional diesel since 1982, using palm oil derived fuel. Numerous studies have shown that most exhaust emission encountered with conventional diesel fuel are reduced with biodiesel,with the exception of nitrogen oxides (NO_x). This paper is reported on the effect of hydroxylated compounds on the exhaust gas emission and fuel properties of palm biodiesel. Fuel properties tested are viscosity, specific gravity, energy content, pour point and flash point. No significant decrease in the energy content when 5% (wt/vol) of hydroxylated compounds were added into palm biodiesel, however the viscosity is increased about 20%. There is a correlation between hydroxyl value of the compound and the reduction of the flame temperature. Higher hydroxyl value resulted in more significant reduction of flame temperature. The engine test run using the most promising compound showed a decrease in the NO_x emission.