The fuel properties of rubber seed oil methyl ester in
comparison with that of other esters is shown in Table 2
[5,7–9,14–16]. The experimental procedures adopted for the
fuel property analysis are also given in Table 2. Most of the
fuel properties of rubber seed oil methyl ester are quite
comparable to those of other esters and diesel. The
chromatographic analysis supports that the biodiesel contains
large amount of C18. The C, H, O composition of
rubber seed oil methyl esters are 76.85, 11.82 and 11.32%,
respectively. The present results obtained show that, the
transesterification process improved the fuel properties of
the oil with respect to specific gravity, viscosity, flash point
and acid value. The comparison of these properties with
diesel shows that the methyl ester has a relatively closer fuel
property values to that of diesel (than that of oil). The
viscosity of biodiesel is closer to that of diesel. Hence, no
hardware modifications are required for handling this fuel
(biodiesel) in the existing engine. The calorific values of
methyl esters are lower than that of diesel because of their
oxygen content. The presence of oxygen in the biodiesel
helps for complete combustion of fuel in the engine. The
flash point of rubber seed oil is lowered by transesterification
but it is still higher than that of diesel. A small
percentage addition of biodiesel with diesel increases the
flash point of diesel. Hence, it is safer to store biodiesel–
diesel blends as compared to diesel alone. The properties of
biodiesel are compared with ASTM biodiesel standards.
The tested properties of methyl esters of rubber seed oil are
found to be in reasonable agreement with ASTM 6751.