Environmental Engineering Reference
In-Depth Information
DID YOU KNOW?
The availability of biomass fuel sources is not consistent, as reliance on the
forest and agricultural residual sources is quite uncertain (Karthick, 2010).
that would stretch the limits of an aggressive research and development program,
such systems will require acres of land. At such large sizes, it is more appropriate
to think of these operations on the scale of a farm. Waste carbon dioxide is readily
available from a number of sources. Every operation that involves combustion of
fuel for energy is a potential source. Generally, coal and other fossil fuel-fired power
plants are targeted as the main sources of carbon dioxide, as typical coal-fired power
plants emit flue gas from their stacks containing up to 13% carbon dioxide. This high
concentration of carbon dioxide enhances the transfer and uptake of carbon dioxide
in the ponds. The concept of coupling a coal-fired power plant with an algae farm
provides a win-win approach for recycling the carbon dioxide from coal combustion
into a usable liquid fuel.
J
atropha
to
B
iodiesel
The uninformed or misinformed might flinch when they discover that a byproduct of
the plant
Jatropha curcas
—yes, the same plant known in some places as “black vomit
nut” and in others as “bellyache bush” or “tuba-tub”—is being used as a product that
has some credible value.
Jatropha
shrubs are inedible plants that grow mostly in
countries such as the Philippines.
Jatropha
is resistant to drought and can easily be
planted or propagated through seeds or cuttings. It starts producing seeds within 14
months, but reaches its maximum productivity level after 4 to 5 years. The
Jatropha
plant can produce an oil content of 30 to 58%, depending on the quality of the soil
where it is planted. The seeds yield an annual equivalent of 0.75 to 2 tons or 1892 liters
of biodiesel per hectare. The plant remains useful for around 30 to 40 years and can
be planted in harsh climates where it would not compete for resources needed to grow
food. Along with having the advantage of being a renewable fuel source, the
Jatropha
plant also reduces greenhouse gas emissions and our dependence on oil imports.
p
ros
and
c
ons
oF
B
iodiesel
The greatest advantage of biodiesel over conventional petroleum diesel is that bio-
diesel comes from renewable resources. The supply can be grown, over and over
again. Biodiesel combustion also produces fewer emissions (except for nitrous
oxides) than combustion of an equal amount of petroleum diesel. The widespread use
of biodiesel can also reduce the dependency on imported oil. From a safety stand-
point, biodiesel is safer than petroleum diesel because it is less combustible. From
an environmental standpoint, when accidentally spilled, biodiesel is not persistent
within environmental media (air, water, soil) because it is biodegradable. Biodiesel
can also be produced from waste products such as cooking oils and grease.
