Page 94 - Advances in Eco-Fuels for a Sustainable Environment

68 Advances in Eco-Fuels for a Sustainable Environment

3.2.2 Prospects of nonedible oils for biodiesel production

There is a growing concern with the use of edible oil because it competes with a food
source, which can result in a decline in food production and supply [7]. This has
shifted attention to the use of nonedible oil as feedstocks for biodiesel production.
Nonedible oil offers interesting advantages. It has been reported that nonedible oil
can easily be cultivated without intensive care and very minimal efforts are required
to sustain its growth [1, 40]. The adaptability of nonedible oil plants to the harsh envi-
ronment has further encouraged their cultivation. For instance, the pongamia tree can
be planted in degraded lands, wastelands, or fallow lands and is highly tolerant to
salinity. Some nonedible oil offers a long range of life cycle, which eliminates the
need for yearly replanting and still offers a sustained, reasonably high yield even with
minimum irrigation [1]. The cost of a plantation in terms of per kg oil for nonedible oil
crops is lower than the plantation cost for edible oil crops, with an exception for palm
oil. The high requirement on soil nutrients and a good irrigation system during the
cultivation of edible oil crops such as soybeans, rapeseed, and oil palm have led to
higher plantation costs [1]. The various advantages of nonedible oil have been well
reported [4], and are listed below:
(1) The adaptability of cultivating nonedible oil feedstocks in marginal land and non-
agricultural areas with low fertility and moisture demand.
(2) They can be grown in arid zones (20cm rainfall) as well as in higher rainfall zones and
even on land with their soil cover. Moreover, they can be propagated through seed or
cuttings.
(3) They have huge potential to restore degraded lands, create rural employment generation,
and fix up to 10 tonnes/ha/year CO 2 emissions.
(4) They do not compete with existing agricultural resources.
(5) They eliminate competition for food and feed. Nonedible oils are not suitable for human
food due to the presence of some toxic components in the oils.
(6) They are more efficient and more environmentally friendly than the first-generation feed-
stocks. Conversion of nonedible oil into biodiesel is comparable to the conversion of edi-
ble oils in terms of production and quality.
(7) Less farmland is required and a mixture of crops can be used. Nonedible oil crops can be
grown in poor areas and wastelands that are not suitable for food crops.
(8) The nonedible feedstock can produce useful byproducts during the conversion process,
which can be used in other chemical processes or burned for heat and power generation.
For instance, the seed cakes after oil expelling can be used as fertilizers for soil
enrichment.
(9) Most of the nonedible oils’ plants are highly pest and disease resistant.
(10) The main advantages of nonedible oils are their liquid nature portability, ready availabil-
ity, renewability, higher heat content, lower sulfur content, lower aromatic content, and
biodegradability.
There are many nonedible oils that have been previously reported for biodiesel produc-
tion, among which are Jatropha curcas L. (Jatropha oil), Azadirachta indica (Neem oil),
Euphorbia lathyrisl (Caper spurge oil), Oryza sativa (Rice bran seed oil), Pongamia pin-
nata (Karanja), Putranjiva roxburghii (Putranjiva oil), Thevetia peruvianam (Yellow
oleander oil), Madhuca indica (Mahua oil), Calophyllum inophyllum (Tamanu oil).