The present work studies the influence of waste fish oil, palm oil and waste frying oil as rawmaterial on biodiesel properties.
The experimental planning was executed through acid esterification (6:1 methanol to oil ratio, 1 wt.% sulfuric acid, at 60 °C, 1 h) followed by transesterification (9:1methanol to oil ratio, 0.5wt.% sodiumhydroxide, at 60 °C for 1 h).
Biodiesel samples showed yield higher than 82%, reaching 90% for palm oil (33.3 wt.%) and waste frying oil (66.7 wt.%) biodiesel.
FAME content was higher than 92.3% and had amaximumof 98.5% for waste fish
oil (33.3 wt.%) and palm oil (66.7 wt.%) biodiesel.
Special cubic models were used to fit experimental data, and
were optimized by response surface methodology and multi-objective optimization. Viscosity (4.3 mm2/s) and COM (2.5 °C) were minimized when pure fish oil was used as raw material, whereas IP maximum (22.0 h) was found for palm oil biodiesel.
Multi-objective optimization evidenced that although the use of the pure oils
as feedstock presented more advantages to biodiesel properties, the waste fish oil (42.1 wt.%) and waste frying oil (57.9 wt.%) mix is beneficial, if the aim is IP (20%) and COM (80%) improvement.