Abstract:
As a renewable energy source for diesel engine, most of the biodiesel are produced from edible plant oil. There are large amount of non-edible type oil and fats are available without any
commercial use. The constraint with alkaline esterification of these underutilized plant oil is
the availability of large amount of free fatty acids (FFA). These free fatty acids quickly followed saponification process to form soap and it inhibit the formation of ester. This study was
focused to assess the potential of non-edible oil seeds, Koan (Schleichera oleosa) for producing
biodiesel and the properties of the biodiesel were comparatively assessed with mineral diesel
(Lanka Auto diesel) using ASTM standard. The oil was extracted from air dried Koan seeds by
a Soxhlet extractor using ether as the solvent. The seed oil content was observed as 55.6% (dry
basis). As FFA content of oil was higher as 6.7 mg NaOH needed to neutralized. A two-step
transesterification process was practiced. The first step, acid catalyzed esterification to reduce
the FFA of the oil. The second step, alkaline catalyzed transesterification process convert the
oil to the methyl ester. The biodiesel/ Koan methyl ester was characterized for its properties.
The results showed that 4.95 mm2
s
-1 of Kinematic Viscosity, 40.77 MJkg-1 of calorific value,
7.26 of pH value, 0.52 of acid number, and slight Tarnish in Copper strip corrosion test. Those
values are in the acceptable limits of ASTM standard of biodiesel. But flash point value, ash
content and Specific Gravity were observed as 188 ◦C, 0.81% and 0.8592 respectively and those
aren’t in the limits of ASTM standard.
