Environmental Engineering Reference
In-Depth Information
FIGure 25.2 (see color insert)
Photographic view of test engine.
FIGure 25.3 (see color insert)
Photographic view of pressure measuring setup.
esters that have different physical and chemical properties. Therefore, the fatty acid ester profile of
biodiesel affects the fuel properties.
The important fuel properties discussed in this section are density, heating value, cetane number,
iodine value, fatty acid ester composition, and percentage of unsaturated fatty acids. The results
of fuel tests on different biodiesel fuels are summarized in Table 25.4. The fatty acid methyl ester
composition of various test fuels is shown in Table 25.5.
A correlation analysis was made to find out the degree of linear association between different
biodiesel properties and percentage of unsaturation. The Pearson product moment correlation coef-
ficient between different properties and the percentage of unsaturation is shown in Table 25.6.
The formula used to calculate the Pearson correlation coefficient (
r
) is shown in equation (25.1):
Σ(
XXYY
XXYY
−
)(
−
)
(25.2)
r
=
,
(
−
) (
2
−
)
2
where
r
is the Pearson correlation coefficient,
X
is the percentage of unsaturation, and
Y
represents
properties.
