Page 126 - Advances in Eco-Fuels for a Sustainable Environment

98 Advances in Eco-Fuels for a Sustainable Environment

Jatropha oil (Jatropha curcas)
Jatropha oil is nonedible and is considered a potential source for producing biodiesel.
Jatropha curcas is a perennial tree belonging to the family Euphorbiaceae and is grown
in subtropical regions such as Central America, Africa, the Indian subcontinent, and
other countries in Asia [17]. The oil content in Jatropha seeds is 35–40wt%, and in
the kernel, the oil content is 50–60wt% [37]. Jatropha oil exhibits properties such as
low acidity, low viscosity as compared to castor oil, good oxidation stability as com-
pared to soybean oil, and better cold properties when compared to palm oil. Thus it
is considered as the most valuable end product from the seeds [37]. The methyl esters
of Jatropha oil exhibit poor low-temperature operability because it contains a relatively
high percentage of saturated fatty acids [17]. The fatty acid profile of jatropha oil shows
the presence of saturated fatty acids such as myristic acid (0.5–1.4wt%), palmitic acid
(12–17wt%), stearic acid (5–9.5wt%), arachidic acid (0.3wt%), and unsaturated fatty
acids such as oleic acid (37–63wt%) and linoleic acid (19–41wt%). Other than the use
of Jatropha oil in the production of biodiesel, Jatropha trees are known to reduce the CO 2
levels in the atmosphere [12]. As per the work carried out by Nisar et al. [37],a jatropha
methyl ester yield of 96.1% has been obtained at a reaction temperature of 70°Cfor 9:1a
methanol to oil molar ratio and using 6% (wt of oil) KOH catalyst supported on calcined
animal bones. Some of the properties of jatropha methyl esters include a kinematic
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viscosity of 2.35–2.47mm /s, a calorific value of 39.65–41.63MJ/kg, an acid
value 0.61–0.66mg of KOH/g, a cetane number of 60.74–63.27, and a pour point of
6°Cto2°C [38].

Pongamia oil (Pongamia pinnata)
Pongamia (Pongamia pinnata) is also called Karanja. It is a medium-sized deciduous
tree that becomes an adult in 4–7years and grows fast in humid and subtropical envi-
ronments [17]. During adverse conditions such as drought, heat, frost, salinity, etc.,
Pongamia can survive. The fruit contains one to two kidney-shaped kernels. It is found
from the Himalayan foothills to Kanyakumari in India. The viability period of the
Karanja fruit is 1year, and the seed number varies from 9 to 90kg per tree. The oil
content in the Karanja seed is 27–39wt%. In Indian states such as Tamil Nadu, Kerala,
Karnataka, Maharashtra, and Andhra, around 10,000tonnes of Karanja seeds are
annually traded. The Karanja oil yield is 2.0–4.0tonnes/ha/year [38]. Karanja oil,
which has been directly extracted, has most of the physical and chemical properties
similar to diesel. Preheating of Karanja oil is required to start the diesel engine because
of its high viscosity. Oleic acid (45–70wt%) is the primary fatty acid found in Karanja
oil, followed by linoleic acid (10.8–18.3wt%), palmitic acid (3.7–7.9wt%), and
stearic acid (2.4–8.9wt%) [12]. Patel and Sankhavara [38] found that around 97%
conversion of crude Pongamia oil to biodiesel has been obtained at a reaction temper-
ature of 65°C for a methanol to oil molar ratio of 6:1 and using 1% (wt of oil)
KOH catalyst. Pongamia methyl ester physical properties include a kinematic viscos-
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ity of 5.52–5.59mm /s, a calorific value of 37.8–39.69MJ/kg, an acid value
of 0.72–0.76mg of KOH/g, a cetane number of 59.68–60.90, and a pour point of
3°Cto 1°C [38].