Page 102 - Advances in Eco-Fuels for a Sustainable Environment

Prospects of biodiesel feedstock as an effective ecofuel source and their challenges 75

production. The amount of seeds that can be harvested per hectare of land is around
600kg and under optimal conditions, the amount can increase to 1200kg. The oil con-
tent in the seed is about 36%–41% and the kernel contains about 17%. There is an
absence of nicotine in tobacco oil. As a nonedible oil, it possesses physical and chem-
ical properties and shows thermal properties similar to other vegetable oils. It is
already gaining acceptance in biodiesel production. At optimized conditions, a yield
of 91% of biodiesel from the oil is possible. However, the biodiesel obtained from
tobacco oil does not meet the limits of the oxidation stability and iodine number of
the European biodiesel standard. The use of antioxidants has been reported to improve
the oxidative stability of the biodiesel. The saturation, monosaturation, and poly-
saturation of fatty acid present in the oil are, respectively, 14.90%, 14.92%, and
70.25% [7, 12, 19, 44].

3.2.2.8 Rubber seed oil (Hevea brasiliensis)

The rubber tree belongs to the same family as the Caper Spurge—Euphorbiaceae. It
is native to Brazil and is distributed in countries such as Nigeria, Ghana, Liberia,
Malaysia, Indonesia, Thailand, and Sri Lanka. It takes about 12years for the plant
to be available for tapping. The tree accounts for 99% of the total world production
of natural rubber. The tree enjoys wide planting in Southeast Asia, which accounts for
97% of the world’s production. It grows on a well-drained acid soil of clay or sandy
soil and requires heavy rainfall; its height reaches 34m. The rubber seed weighs
between 2 and 4g and a tree can give up to 500g. On a hectare basis, approximately
150kg of seeds can be realized with the rubber oil yield of 80–120kg (wt%). The
brown rubber oil is nonedible in which the seed contains 40%–60% of the oil and
the kernel contains 50%–60% of the oil. The oil obtained from rubber has not really
been explored for industrial purposes. Research is being done to investigate the pos-
sible conversion of rubber oil to biodiesel. A high yield of 96.4% of biodiesel based on
oil is possible under the careful combination of process parameters. The saturation,
monosaturation, and polysaturation of fatty acid present in the oil are, respectively,
18.90%, 24.60%, and 55.90% [1, 7, 12, 19, 44].

3.2.2.9 Rice bran oil (Oryza sativa)
It is a brown layer cuticle found between the rice grain and the paddy husk. It is a low-
grade, cheap material obtained as the byproduct in the refining of white rice. It is
grown primarily in China and India. It is rich in protein and other chemicals that have
high commercial value. It contains lipids, minerals, and vitamins. The composition of
rice bran obtained depends on the rice type, climatic conditions, and the methods used
in processing. The amount of oil obtained from the bran is around 16–32wt%, though
this value depends so much on the variety of rice processed and the degree of milling
used. The presence of lipase in the bran makes it have a high free fatty acid and this
makes about 60%–70% produced to be nonedible. The rice bran oil is a low-cost feed-
stock that has been underutilized. It is available in large quantities in countries where
rice is largely cultivated. The use of rice oil has not really been investigated for