Page 90 - Advances in Eco-Fuels for a Sustainable Environment

64 Advances in Eco-Fuels for a Sustainable Environment

3.2.1.6 Moringa

Moringa (Moringa oleifera) is already being grown as an ornamental in much of the
world’s tropical regions and it has begun to naturalize in some regions. The ben tree
(Moringa peregrina) grown from North Africa to the Middle East is tolerant of
extremely arid conditions and it is the source of ben oil [24]. Moringa produces pods
such as long green beans that can be cooked and eaten when they are pencil thin, but
must be scraped off when the pod gets fatter and tougher like an artichoke [24]. Edible
horseradish-flavored seeds produce valuable oil similar in composition to olive oil and
are used in cooking and as a fuel [24]. The seeds and the seedcake residue left after
pressing the oil are used to purify drinking water as they are both a flocculant (remov-
ing solids) and an antimicrobial [24]. Pod yields can be 31tonnes per hectare and when
mature, the pods are filled with small edible seeds that can be pressed for oil to pro-
duce about 250L (66gal) per hectare [24].

3.2.1.7 Rapeseed/canola

Canola is an edible variety of rapeseed with a low percentage of erucic acid and low
levels of glucosinolates. It was developed by Canadian plant breeders in the 1970s.
The word “Canola” was coined from “Canada” and “Oleo” (Oil) and is applied to vari-
eties of rapeseed with 2% or less erucic acid and <30μmol of glucosinolates per gram
of oil-free meal. Much of the rapeseed grown in Europe is of canola quality but retains
the name rapeseed, probably because the word “rape” does not have the negative con-
notations in Europe that it has in English-speaking countries. Currently, about 84% of
the world biodiesel production is met by rapeseed oil, 13% from sunflower oil, 1%
from palm oil, and 2% from soybean oil and others [1]. Winter rapeseed oil as a diesel
fuel was studied because of its high yield, high oil content (45%), and high erucic acid
content (46.7%) [37]. The rate of gum formation of winter rapeseed oil was five times
slower than that of high linoleic (75%–85%) oil. The viscosities of 50/50 and 70/30
blends of winter rapeseed oil and diesel and whole winter rape oil were much higher
(6–18 times) than No. 2 diesel [37]. A blend of 70/30 winter rapeseed oil and No. 1
diesel was used successfully to power a small single-cylinder diesel engine for 850h.
No adverse wear and no effects on lubricating oil or power output were noted [37].
Canola oil is much more viscous than the other more commonly tested vegetable
oils. At 10°C, the viscosity of canola oil was 100cSt, a 75/25 blend of canola oil and
diesel fuel was 40cSt, a 50/50 blend was 19cSt, and the viscosity of diesel fuel was
4cSt [37]. The flow rate of canola was lower than diesel at the same pressure and it
dropped to almost zero at 4°C. Viscosity can be lowered by blending with pure eth-
anol [37].At 37°C, the viscosity of canola oil and 10% ethanol was 21.15cSt while
that of straight canola oil was 37.82cSt [37].

3.2.1.8 Sunflower
The annual sunflower (Helianthus annuus) was domesticated in the central United
States thousands of years ago and is a top world oilseed crop. Sunflowers are suited
to cold and semiarid regions. Annual sunflower seeds contain 23%–24% protein and