Page 100 - Advances in Eco-Fuels for a Sustainable Environment

Prospects of biodiesel feedstock as an effective ecofuel source and their challenges 73

cycle of between 150 and 200years. The neem tree is affected by drought and in severe
conditions, its leaves drop off. The color of neem oil is light to dark brown with a
characteristic bitter taste. The seed contain about 20–30wt% oil and it produces about
2670kg of oil per hectare. The oil has a potential of producing biodiesel to comple-
ment conventional biodiesel. It has been reported that the biodiesel produced from
neem oil gives optimum yield and properties similar to conventional diesel. The free
fatty acid content of neem oil is about 21.6%, which can limit its use. However, this
value can be reduced to as low as 1% when pretreated with an acid catalyst. The sat-
uration, monosaturation, and polysaturation of fatty acid present in the oil are, respec-
tively, 37.00%, 44.50%, and 18.50% [7, 11, 12, 19, 42].

3.2.2.3 Polanga (Calophyllum inophyllum L.)

The Polanga tree belongs to the family of the Clusiaceae. It is widely distributed in
Australia, East Africa, Southern coastal India to Malaysia, and Southeast Asia. It
oil is nonedible and the tree is a medium to large evergreen submarine tree [22].It
grows best in deep soil or on exposed sea sands. The annual rainfall requirement is
between 750 and 5000mm. It can grow at a rate of 1m per year if grown on good sites.
The unripe fruit is at first pinkish-green and turns to bright green. When ripe, it turns
dark gray-brown and is wrinkled. The fruits are spherical and arranged in clusters. The
oil in the seed is 65%–75% [7]. The yield of oil per hectare of land is 2000kg. Gen-
erally, the saturation, monosaturation, and polysaturation of fatty acid present in the
oil are respectively 39.00%, 45.20%, and 15.80% [7, 48].

3.2.2.4 Mahua oil (Madhuca indica)

The Mahua tree (Madhuca indica) belongs to the Sapotaceae family. It is a medium to
large tree found mostly in India. The two major species found in India are Madhuca
indica and Madhuca longifolia. It is a nonedible oil with an annual production of
60 million tonnes in India. The Mahua tree now enjoys wide cultivation in Central
Africa. It thrives well in deep clay soil and grows quickly with a height reaching
up to 20m with high adaptability to arid environments. It requires an annual rainfall
of 550–1500mm and a temperature of 46°C. It takes about 10years for the tree to fully
mature and continuous production can be up to 60years. Fresh mahua oil is yellowish
while the commercial oil is greenish yellow. The seed contains 35%–50% oil and the
kernel contains 50% oil, depending on the size and age of the tree. The total oil yield of
Mahua oil per hectare is 2700kg. The oil contains about 20% FFAs and a procedure
for converting this oil to biodiesel is required. The biodiesel obtained from mahua oil
has properties similar to the conventional diesel of American and European standards.
Under optimized conditions, about 98% conversion of mahua oil to biodiesel is pos-
sible. The blend of mahua oil biodiesel with conventional diesel has been found to
result in lower CO, hydrocarbon, and smoke emissions as compared to pure conven-
tional diesel. The saturation, monosaturation, and polysaturation of fatty acid present
in the oil are, respectively, 35.80%, 46.30%, and 17.90% [7, 11, 12, 19, 42, 44].