Environmental Engineering Reference
In-Depth Information
grow on marginal land. It grows best at latitudes from sea level to 1200 m with an optimal annual
rainfall of 500-2500 mm; it is drought and saline tolerant (Scott et al. 2008 and references therein).
Products derived from pongamia have included not only fuel but also traditional medicines, animal
fodder, green manure timber, and fish poison (Scott et al. 2008). As is the case with many of the
emerging energy crops mentioned here, successful establishment of pongamia as a fuel source would
require work in the area of agronomy, plant propagation, genetics, and molecular biology (Scott
et al. 2008). Pongamia has been stated to compare favorably to other emerging energy sources for
biodiesel in terms of land-use requirements (Azam 2005; Scott et al. 2008). Relevant predictions for
biodiesel production from pongamia include 20,000 seeds/year from a 10-year-old tree with 1.8 g
oil/seed (36 kg oil/tree per year) at 350 trees/ha (leading to 12,600 kg oil/ha per year) (Scott 2008).
The fatty acid profile of pongamia consists of oleic acid (40-55%), palmitic acid (5-15%), stearic
acid (5-10%), and linoleic acid (15-20%) with smaller amounts of the longer-chain saturated fatty
acids arachidic acid (C20:0), behenic acid (C22:0), and lignoceric acid (C24:0) (Scott et al. 2008).
However, wide variability in the oil content and fatty acid profile was observed in germplasm
accessions collected in a region of central India (Mukta et al. 2009). The cetane number has been
reported as 55.84 (Scott et al. 2008), which appears to agree with the given fatty acid profile.
However, the cloud point is reported as 8.3°C (Scott et al. 2008), which would coincide with the
saturated fatty acid content reported but would also render this feedstock of reduced interest for use
in more moderate climates.
33.2.2 m
ahua
Another oil that has been reported as an energy source relatively frequently in the literature is
mahua (
Madhuca indica
) oil. Mahua is a forest tree growing in many parts of India (Kumari et al.
2007). The oil (fat) derived from it has a very high content of saturated fatty acids (C16:0 and C18:0),
leading to poor cold-flow properties of the resulting biodiesel, probably even problematic in warmer
climates.
33.2.3 m
oringa
o
il
A comprehensive review (Morton 1991) provides detailed information on moringa (
Moringa
oleifera
).
It is also called horseradish tree and various other names. Similar to pongamia, moringa
is a single-genus family of oilseed tree species that grows in tropical and subtropical regions and
tolerates drought and poor soil. The kernels contain 30-49% oil (Sengupta and Gupta 1970).
Moringa, a single-genus oilseed tree is truly wild only in the western Himalayas and Punjab was
cultivated in India and distributed to other parts of tropical Asia and Oceania and is now also
grown in the Caribbean, parts of Africa and Latin America, and in the United States (Morton
1991 and references therein). Almost all parts of the tree have been used in folk medicine (Morton
1991). Various parts have been used for nutritional purposes and nonphysiological applications
(Morton 1991). Moringa oil is also known as “ben oil” or “behen oil” because of its content of
behenic (docosanoic) acid. The absence of linolenic acid and small amounts of linoleic acid are
partially responsible for the relatively high oxidative stability of the oil (Sengupta and Gupta 1970).
Biodiesel has been prepared from moringa oil (Rashid et al. 2008). This biodiesel fuel is discussed
in Section 33.2.6.
33.2.4 r
icE
B
ran
o
il
Rice bran oil (
Oryza sativa
) is an edible oil of nutritional value with a nutlike taste that finds use
in cooking and nutritional applications. It appears that this could be a biodiesel feedstock that
is significantly affected by the food-versus-fuel issue. Rice bran oil is ultimately derived from
