Page 103 - Advances in Eco-Fuels for a Sustainable Environment

76 Advances in Eco-Fuels for a Sustainable Environment

biodiesel production. However, the resultant oil can be used for biodiesel production,
giving a biodiesel that is economical and affordable. The saturation, monosaturation,
and polysaturation of fatty acid present in the oil are, respectively, 22.00%, 40.83%,
and 37.40% [7, 11, 19, 42].

3.2.2.10 Castor oil (Ricinus communis)

Ricinus communis is also referred to as castor beans. It is a nonedible oil seed crop that
belongs to the Eurphorbiaceae family. Its growth is widely distributed to areas such as
India, the United States, China, Brazil, Australia, Central Africa, Argentina, Thailand,
Russia, and the Philippines. The major exporters of castor oil are India, China, and
Brazil with India being the highest exporter. The castor tree or shrub can grow above
10m and reach an age of 4 years with a growth of between 2 and 5m in one growing
season in the presence of adequate sunlight, heat, and moisture. Castor is a drought-
resistant tree that has the potential of surviving in any type of soil. A good distribution
of rainfall of between 500 and 600mm, a temperature of 15–38°C, and low humidity
during the growing period ensure maximum yield. It does not compete with arable
land as it can grow on marginal land with tolerance for varying weather conditions.
The seed of the castor tree contains between 45% and 50% of oil. It is a viscous, pale
yellow, nonvolatile, and nondrying oil whose contents depend on environmental con-
ditions. The yield of oil per hectare is 1188kg. It possesses a good shelf life superior to
other vegetable oils and is resistant to rancidity unless under high and excessive heat.
It contains toxins such as ricin and ricinine that are poisonous for human and animal
consumption. Castor oil has been identified as a potential feedstock for the production
of biodiesel but the fact that it is considered a weed by many agricultural producers has
limited its feasibility of producing substantial amounts of biodiesel. The saturation,
monosaturation, and polysaturation of fatty acid present in the oil are, respectively,
22.00%, 40.83%, and 37.40% [7, 11, 12, 19, 42].

3.2.3 Animal fats as feedstock for biodiesel production

Greases, fats, and oils are lipids. Animal fats are lipids sourced from animals but oils
are obtained from plants and/or their seeds. Unlike the oils that exist as a liquid at room
temperature, animal fats and greases are congealed or solid in nature. This establishes
a major distinction between the physicochemical properties of oils and those of fats.
Fats, greases, and oils share resemblances as both are composed of triglycerides. Many
commercial practices engage in extracting oil from rendered tissue fats and applying
them for biodiesel production [50, 51]. Animal fats are a byproduct of the whole meat
chain. They are only obtained in relation to the raising of animals for wool, meat, egg
production, etc. The production of animal fats will not increase by virtue of increasing
demand but is only dependent on the level of demand for animal products such as eggs,
meat, or wool production [52].
Animal fats are classified into edible and nonedible fats. The edible fats are the
byproduct of fresh slaughters declared for human consumption after thorough veter-
inary inspection. Beef tallow is one of the common examples. Examples of the