Page 91 - Advances in Eco-Fuels for a Sustainable Environment

Prospects of biodiesel feedstock as an effective ecofuel source and their challenges 65

47%–50% oil. The yield of annual sunflowers can be as high as 5.7tonnes per hectare
of dry clean seed [24]. There are many perennial sunflowers (Maximilian sunflower,
Jerusalem artichoke, stiff sunflower, Cusick’s sunflower, etc.) that also have protein
and oil-rich seeds; work is also under way to develop perennial edible sunflowers with
competitive yields. Maximilian sunflower (Helianthus maximiliani), Jerusalem arti-
choke (Helianthus tuberosus), and stiff sunflower (Helianthus pauciflorus) can grow
in boreal through warm temperate semiarid conditions while Cusick’s sunflower
(Helianthus cusickii) can grow in arid conditions on terrible soils but is less tolerant
of boreal conditions [24].
Sunflower oil is priced higher than soybean and canola oils due to demand from
the food processing industry. Therefore, its use as a feedstock for commercial bio-
diesel production may not be economically feasible and its price premium may make
it prohibitive to use for biodiesel production. The most advanced work with sun-
flower oil occurred in South Africa because of the oil embargo [37]. Crude,
degummed, and degummed-dewaxed sunflower oils as well as crude, degummed,
and alkali-refined cottonseed oils were tested using a single-cylinder precombustion
chamber engine. The results were negative [37]. The processed oils that were slightly
better than crude oils were not suitable for use as alternative fuels, even though they
performed satisfactorily for a short time. The oils were not suitable because of car-
bon deposits and lubricating oil fouling. A B25% sunflower biodiesel with petroleum
diesel had a viscosity was 4.88cSt at 40°C while the maximum specified ASTM
value is 4.0cSt at 40°C. It was considered not suitable for long-term use in a
direct-injection engine [37].

3.2.1.9 Soybean
Annual soybeans (Glycine max) are a top global crop. Some researchers at the Uni-
versity of Illinois have had success in crossing annual soybeans with an Australian
perennial soybean (Glycine tomentella), with the goal of adding disease resistance
to annual soybeans. However, their efforts have given some insights into the tech-
niques of perennializing the annual soybeans [24]. Soybeans are fast becoming a lead-
ing crop in the grain and oilseed industry as their production is rising annually,
matched with a rise in global demand. The key drivers in the increasing soybean pro-
duction are the United States, Brazil, and Argentina, which collectively contribute
81% to the global soybean production.
The vast majority of soybeans grown in the United States are feed grade, not for
human consumption. All soybeans for human consumption in the United States can be
grown on about 100,000 acres of land. Feed soybeans are crushed into about 80% pro-
tein, 19% oil, and 1%–2% fiber, and as animals do not use or absorb the oil, livestock
producers do not want the natural soybean oil but prefer the soybean protein, which is
mixed with corn starch for an energy source, in their feed formulations. The additional
value of selling the soybean oil for biodiesel allows the protein price to stay low, cov-
ering farmers’ costs. Livestock producers understand these economics, so they are
supportive of biodiesel production from soybean. This is in contrast to corn where