In this study, biodiesel was produced from a naturally grown green algae
(spirogyra). The algae were cultivated in an open pond for 180 days without
any fertilizers or nutrients. The dried algae powder to oil yield and
significant fuel properties of viscosity, density, cetane number, calorific
value, flash point, pour and cloud points are investigated for B10 to B100
blends. The results of solvent oil extraction show that at a 1:2 (algae
powder to solvent) ratio and 65oC, algae oil yield was observed as 22.66%.
Furthermore, Box-Behnken assisted response surface optimization technique
was implemented. From the 29 random experiments, 96.24% spirogyra algae oil
biodiesel (SAOBD) yield was achieved under the optimum conditions of 50oC,
180 minutes, the molar ratio of 9:1 and catalyst concentration of 0.5 wt%.
The fatty acid composition (FAC) by gas chromatography reveals that 73.95
wt% saturated FAC was observed in SAOBD. The significant fuel properties are
measured by following ASTM-D6751 standards and 40% SAOBD in diesel fuel
could possibly be an optimum blend ratio for engine experimentation.
Finally, regression equations with high correlation coefficients (R2) were
developed for the fuel properties to predict the various blend ratios.