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Commercial alcohol is produced from ethylene hydration while ethanol
biofuel is made from the fermentation of sugar or converted starch
contained in grains and other agricultural products. Ethanol biofuel has
been made from corn and wheat. This development has been initially thought
of as good in that it increases demand for farmer's
products and provides increased employment
opportunities.
However, it has been argued that fuel production from
agricultural crops reduces the amount of such crops available for feeding.
Consequently, to avoid dependence on food-based feedstock, researches are continuously being conducted to identify new
feedstock (plants) that are dedicatedly planted for fuel production.
Some of the plants that are planted specifically for the
generation of
ethanol and methanol,
include:
switchgrass, hemp,
hybrid
willow,
hybrid poplar (cottonwoods)
and sugarcane.
For use in vehicle engines, ethanol is blended with gasoline to produce a fuel called "gasohol".
Gasohol can be used in gasoline-powered vehicles manufactured since the
1980's. Similar to Biodiesel blend, ethanol
blend is represented as Exx, where xx is the percentage of the ethanol in
the gasohol. For instance, a 10% ethanol to 90 % gasoline blend is
represented as E10; 15% ethanol to 85% gasoline blend as E15 etc.
Most gasoline-powered vehicles can run on a E10 blend. This blend is
already available in several service stations in North America. Some
vehicles are specially manufactured to operate on an E85 ethanol blend
(i.e. 85% ethanol to 15% gasoline). The 15% gasoline is needed to assist in engine starting because
pure ethanol is difficult to ignite in cold weather. In other words, E100
dependent cars may not be effective year round in very cold regions. The
E85 blend cannot be used in standard gasoline vehicles, but
only in vehicles designed to use high ethanol blend. However,
vehicles designed to run with a high ethanol blend can also operate using
gasoline when necessary.
Ethanol burns more cleanly and completely than gasoline.
Ethanol is renewable and is better for the environment. Though the
conversion of biomass (feedstock) produces GHG, on a Life Cycle basis,
Ethanol reduces greenhouse gas (GHG)
emissions. This is so because less emissions are produced during ethanol
(or gasohol)
usage and the plants used to produce the ethanol served as carbon sink
during their days of growing.
Blended ethanol (i.e. Gasohol) seems to have slightly lower energy than
gasoline. 1 gallon of pure ethanol contains about 66 percent as much
energy as 1 gallon of gasoline and 1 gallon of E85 (85% ethanol to 15%
gasoline blend) contains about 71 percent as much energy as 1 gallon of
pure gasoline. E10 blend can be used directly in gasoline engines to
produce same level of service without modifications to the gasoline
engine. For higher blends (e.g. E85), larger fuel tanks are designed
and larger quantity of gasohol is required to produce similar service
levels as the gasoline fuel. Besides the larger fuel tank required,
other modifications required in migrating from a gasoline-powered car
to a high ethanol blend powered cars are:
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Modifications to the engine's intake valves,
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Modifications to the fuel-injection system;
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Modifications to the ignition system; and
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Replacement of all vehicle materials that could be destroyed by alcohol
with materials that are alcohol resistant materials. Materials such as
zinc, lead, magnesium, aluminum, plastics and rubbers, that are commonly
used in gasoline-powered vehicles are not alcohol proof and can be broken
down by alcohol. These materials will have to be replaced with alcohol
resistant materials such as stainless steel. The fuel tank and fuel lines
of most Flex-Fuel Vehicles (FFV) that use E85 blend are made of stainless
steel.
Ethanol
is produced in
large heated tanks called digesters. Plant materials and chemicals or
yeasts are added to the
digester. The process converts cellulose in the plant
materials into sugars and then the sugars are converted into alcohol
through fermentation.
Other alcohols that fall
in the category of ethanol are methanol and butanol
For in-depth discussion on ethanol and other biomass energy sources, we recommend that you get
a copy of
Clean Energy Fuels a book written by Dr. Dele Morakinyo one of the contributors to EnvironBusiness.com.
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