Environmental Engineering Reference
In-Depth Information
for the success of its commercialization and market acceptance. Some important issues on the biodiesel
quality control involve monitoring of the transesterification reaction, quantification of mono-alkyl
esters, free and bonded glycerol, and determination of residual catalysts and alcohol. Chromatography
and spectroscopy are the most commonly used analytical methods for biodiesel analyses.
Biodiesel can be blended with diesel fuels and used in diesel engines with few or no modifica-
tions. Depending upon the volume of biodiesel in a blend, it is designated (i.e., for 20% volume of
biodiesel, the blend is designated as B20, for 40% biodiesel in the blend, it is designated as B40, and
so on). But, the fuel properties of biodiesel-diesel fuel blends change with the amount of biodiesel
in the fuel mixture because biodiesel has different fuel properties compared with conventional
diesel fuel. There are several key properties of biodiesel that need to be characterized before using
biodiesel-diesel fuel blends in a diesel engine. These properties include kinematic viscosity, density,
pour point, flash point, acid value, sulfated ash, total and free-glycerin, water content, carbon resi-
due, etc. and are summarized in Table 14.8. Jatropha biodiesel has comparable fuel properties with
those of diesel and it conforms to the latest U.S. and European standards for biodiesel.
14.4.3.1 density
The densities of jatropha oil (JO) and jatropha biodiesel (JB) are approximately 7.52 and 2.94%
higher than that of diesel, respectively (Tables 14.4 and 14.8). Thus, the density of JO is reduced by
approximately 4.26% in its conversion to JB. The higher density of JO and JB as compared with die-
sel may be attributed to the higher molecular weights of the triglyceride molecules present in them.
taBle 14.8
Fuel characteristics of Jatropha Biodiesel
Biodiesel standards
JB
Jatropha
ethyl ester
astm
d6752
dIn
v 51606
Fuel Properties
diesel
range
mean
Density (g/cm
3
)
0.850
0.864-0.880
0.875
0.89
0.86-0.90
0.87-0.90
Kinematic viscosity at 30-40°C (cSt)
2.6
4.84-5.65
5.11
5.54
3.5-5.0
3.5-5.0
Calorific value (MJ/kg)
42
38.45-41.00
39.65
-
-
-
Cetane number
47.68
50-56.1
52.3
59
Min 51
Min 49
Flash point (°C)
68
170-192
186
190
Min 120
Min 110
Acid value (mg KOH/g)
-
0.06-0.5
0.27
0.08
Max 0.8
Max 0.5
Pour point (°C)
-20 to -10
4.2-6
a
-
-
-
-
Water content (%)
0.02
0.07-0.10
-
0.16
Max 0.5
Max 0.3
Ash content (%)
0.01
0.005-0.01
0.013
-
Max 0.02
Max 0.03
Carbon residue (%)
0.17
0.02-0.50
0.18
-
Max 0.3
Max 0.3
Saponification number (mg/g)
-
202.6
-
-
-
-
Iodine number (mg/g)
-
93-106
99.5
-
Max 120
Max 115
Sulfur content (%)
-
0.0036
-
-
Max 0.01
Max 0.01
Monoglycerides (%)
-
0.24
-
0.55
Max 0.8
Max 0.8
Diglycerides (%)
-
0.07
-
0.19
Max 0.2
Max 0.4
Methyl ester content (%)
-
99.6
-
99.3
Min 96.5
-
Methanol (%)
-
0.06-0.09
-
0.05
Max 0.2
Max 0.3
Free glycerol (%)
-
0.015-0.030
-
-
Max 0.02
Max 0.02
Total glycerol (%)
-
0.088-0.100
-
0.17
Max 0.25
Max 0.25
Source:
Modified from Achten, W.M.J., et al.,
Biomass Bioenergy
, 32, 1063-1084, 2008.
a
Sahoo, P.K. and Das, L.M.,
Fuel,
88, 1588-1594, 2009a and Vyas, A.P., Subrahmanyam, N., and Patel, P.A.,
Fuel
, 88,
625-628, 2009.
