W N Maawa - Faculty of Mechanical and Automotive Engineering Technology, Universiti Malaysia Pahang, Pahang, Malaysia
R Mamat - Faculty of Mechanical and Automotive Engineering Technology, Universiti Malaysia Pahang, Pahang, Malaysia
G Najafi - Department of Mechanical and Biosystems Engineering , Tarbiat Modares University, Tehran, Iran
S Sapee - ۴Faculty of Mechanical and Automotive Engineering Technology, Universiti Malaysia Pahang, Pahang, Malaysia

Under the crisis of global warming and drastic climate changing, carbon-neutral renewable energy is considerably proposed as a feasible clean alternative energy to fractionally replace fossilized fuel. To cop up with ever stringent emission regulations, researchers have investigated different types of renewable fuels like biodiesel and water emulsion. The fuel physical characteristics are among the most important parameter to determine the quality of each fuel before it being tested in the engine. The aim of this study is to evaluate the stability period and mean droplet size of the particles and to characterize the physicochemical properties of emulsified biodiesel blend B20 in terms of kinematic viscosity, density and calorific value with different percentage of water; 5%, 10%, 20% and 30%. The tested fuel samples were compared with diesel fuel and blended palm biodiesel (B20). The experimental results show that when the proportion of water were increased in diesel-biodiesel blends, the dispersed water droplets become larger. The stability period in terms of days for emulsion fuels becomes lower when the amount of water were increased to the blends. The least stability period for emulsion obtained by emulsion with 20% and 30% water content which is 2 days. The kinematic viscosity and density of biodiesel emulsions were larger than those of the neat biodiesel. The calorific value for emulsion with 5% water content is comparable to blended fuel and conventional diesel even though there was a slight reduction.

water emulsion, alternative fuel, biodiesel, palm oil, fuel properties