In this study, the work was carried out to investigate the effects of ethanol
proportions on the stabilities and physicochemical characteristics of tri-fuel (Diesel-Biodiesel-
Ethanol). For the first time, tri-fuel emulsions and blended were compared side by side. The
experiment was done with composition having 5%, 10%, 15%, 20% and 25 % of ethanol with
fixed 10% of biodiesel from palm oil origin on a volume basis into diesel. The results indicated
that the phase stabilities of the emulsified fuels were higher compared to the blended fuels. In
addition, tri-fuel composition with higher proportion of ethanol were found unstable with high
tendency to form layer separation. It was found that tri-fuel emulsion with 5% ethanol content
(D85B10E5) was of the best in stability with little separation. Furthermore, tri-fuel with lowest
ethanol proportion indicated convincing physicochemical characteristics compared to others.
Physicochemical characteristics of tri-fuel blending yield almost similar results to tri-fuel
emulsion but degrading as more proportion ethanol content added. Emulsion category had
cloudy look but on temporarily basis. Under the microscope, tri-fuel emulsion and blending
droplet were similar for its active moving about micro-bubble but distinct in term of detection
of collision, average disperse micro-bubble size, the spread and organization of the
microstructure.