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What is Biodiesel?
Biodiesel is a clean-burning alternative fuel, produced from
domestic, renewable resources, such as soy beans or used vegetable oils. Biodiesel contains no petroleum, but it can be blended at
any level with petroleum diesel to create blends, generally called B20 or B5.
In addition to supporting domestic farmers for their soybean crops, a primary
reason for developing alternatives to oil is the creation of U.S. independence from
foreign oil.
Biodiesel also has been shown to improve vehicle
performance with enhanced lubricity and reduction of emissions. It is simple
to use, biodegradable, nontoxic, and essentially free of sulfur and
aromatics. Biodiesel is used by major trucking
fleets, as well as the U.S. military, national
parks, NASA, state transportation departments, major public utility fleets,
environmental companies, farmers and several school
districts nationwide.
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What is the EPAct (Energy Policy Act)?
EPAct is the Energy Policy Act of 1992 that focuses on reducing
motor fuel consumption and mandates alternative fuel use. EPAct's primary emphasis is to reduce U.S. dependence on
foreign oil through the promotion of domestic, alternative transportation
fuels. Provisions of EPAct mandate alternative
fuel vehicle purchases for federal, state and fuel provider fleets, with
the potential of mandates for municipal and private fleets. Alternative
fuel vehicles (AFVs) have the ability to run on biodiesel, compressed natural gas (CNG), liquefied
natural gas (LNG), liquefied petroleum gas (LPG), propane, methanol, ethanol or electric. The federal government, through EPAct, has established mandates for AFV purchases by
federal and state agencies beginning in 1993 and 1997 respectively. EPAct also gives the Department of Energy the authority
to establish mandates for municipalities and private fleets located in
large metropolitan areas. In addition, fuel providers are currently
required to have AFVs as an increasing percentage
of their fleet purchases.
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What are emissions reductions?
Fine
particulate emissions have been identified as a major health risk, the
smaller the particle, the greater the risk. Motor vehicles powered by diesel
engines are a significantly disproportionate contributor of fine particle
pollution and oxides of nitrogen in urban areas.
Biodiesel is the only alternative fuel to have
fully completed the health effects testing requirements of the Clean Air
Act. The use of biodiesel in a conventional
diesel engine results in substantial reduction of unburned hydrocarbons,
carbon monoxide, and particulate matter compared to emissions from diesel
fuel. In addition, the exhaust emissions of sulfur oxides and sulfates (major
components of acid rain) from biodiesel are
essentially eliminated compared to diesel.
Of the major exhaust pollutants, both unburned hydrocarbons and nitrogen
oxides are ozone or smog-forming precursors. The use of biodiesel
in a conventional diesel engine results in substantial reduction of
unburned hydrocarbons, carbon monoxide, and particulate matter. Emissions
of nitrogen oxides are either slightly reduced or slightly increased
depending on the duty cycle of the engine and testing methods employed.
The use of biodiesel decreases solid carbon
fraction of particulate matter as an increased amount of oxygen present in biodiesel enables a more complete combustion process.
Since sulfur is not present in biodiesel, sulfate
fraction associated with petroleum based diesel is eliminated. In addition
to reducing the overall levels of pollutants and carbon, the compounds that
are prevalent in biodiesel and petroleum based
diesel fuel exhaust are different. Research conducted by Southwest Research
Institute on a Cummins N14 engine indicates that the biodiesel
exhaust has a less harmful impact on human health than petroleum diesel.
Biodiesel emissions have decreased the levels of
all largest polycyclic aromatic hydrocarbons (PAH) and nitrated PAH
compounds were reduced by 75-85 percent, according to the National Biodiesel Board (NBB).
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Is Biodiesel safer than petroleum
diesel?
Scientific
research confirms that biodiesel exhaust is less
harmful on human health than petroleum diesel. Biodiesel
emissions have decreased levels of polycyclic aromatic hydrocarbons (PAH)
and nitrated PAH compounds that have been identified as potential cancer
causing compounds. Test results indicate PAH compounds were reduced by 75
to 85 percent, with the exception of benzo(a)anthracene, which was
reduced by roughly 50 percent. One hundred percent biodiesel
and blends of biodiesel with petroleum diesel are
safer to store, handle and use than conventional
diesel.
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Does Biodiesel need special
storage facilities?
In general, the
standard storage and handling procedures used for petroleum diesel can be
used for biodiesel. The fuel should be stored in
a clean, dry, dark environment. Acceptable storage tank materials include
aluminum, steel, fluorinated polyethylene, fluorinated polypropylene
and teflon. Copper, brass, lead, tin and zinc should be avoided.
Biodiesel does suffer from a problem called
oxidation if stored for periods longer than six months. This means that the
fuel will slowly oxidize over time unless an anti-oxidant additive is
blended to the fuel to prevent this process happening.
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Can Biodiesel be used in any
diesel engine?
Biodiesel can be used in any diesel engine, typically
with no modifications to the engine necessary. It performs comparably to
diesel, with similar BTU content and higher cetane.
It offers excellent lubricity and lower emissions compared to petroleum
diesel.
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Are there any precautions to using Biodiesel?
Biodiesel has a solvent effect that may release
deposits accumulated on tank walls or pipes from previous diesel fuel storage
and precautions should be taken when first switching over to Biodiesel. The release of deposits may clog filters
initially and precautions should be taken to prevent these deposits from
getting to the engine fuel filters.
Over time, Biodiesel will soften and degrade
certain types of elastomers and natural rubber
compounds used in older fuel hoses and pump seal systems. Precautions are
needed when using high percent blends to ensure that the existing fueling
system on older engines does not contain elastomer
compounds incompatible with biodiesel.
Manufacturers recommend that natural or butyl rubbers not be allowed to
come in contact with neat biodiesel otherwise
they turn sticky and fall apart. Most vehicles made after 1994 will have
fully synthetic fuel lines and seals so will not suffer from this problem,
but older vehicles need to be monitored.
Biodiesel has a higher gel point. 100 percent biodiesel, referred to as B100, gets slushy at 32°F. A
blend of 20 percent biodiesel, 80 percent regular
diesel, B20, has a gel point of 3 to 10°F, according to the NBB. Like
regular diesel, the gel point can be lowered further with additives such as
kerosene, which are blended into winter diesel in cold-weather areas.
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Does Biodiesel work with older
engines?
Biodiesel can have some methanol left in it from
the production process that uses MethalOxide
during the transesterification process. Methanol
will destroy rubber tubing and seals over time, so older engines without
synthetic seals made from products like Viton,
will need to have rubber parts in the fuel system replaced.
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Who is using biodiesel?
Biodiesel is used by major trucking fleets, as well
as the U.S. military,
national parks, NASA, state transportation departments, major public
utility fleets, environmental companies, city government, farmers and several school districts nationwide.
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What are the American Society of Testing and Materials
(ASTM) standards?
The American
Society of Testing and Materials (ASTM) biodiesel
Task Force began working on a standard for biodiesel
in 1994 and issued Specification D 6751 in 2002 covering all biodiesel fuel bought and sold in the United States. The ASTM biodiesel Standard helps to protect consumers from poor
products and reduce the cost of buying and selling biodiesel.
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Will using Biodiesel impact my
engine warranty?
Manufacturers
warrant their products against defects in materials and workmanship. In
general, use of a particular fuel should have no effect on the materials
and workmanship warranty. Use of biodiesel does
not void the warranty, as this is prohibited by the Magnuson-Moss Warranty
Act. Manufacturers are concerned that extensive use of biodiesel
will result in increased numbers of warranty claims for what are actually
problems caused by the fuel.
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How does Biodiesel help lubricity?
Testing at
labs such as Southwest Research Institute, Standyne
Automotive and Engineering Testing Services have demonstrated that biodiesel provides significant lubricity improvement
over petroleum diesel fuel. Lubricity results of biodiesel
and petroleum diesel using the High Frequency Reciprocating Rig test
indicate that there is a marked improvement in lubricity when biodiesel is added to conventional diesel fuel, even at
blend levels below one percent.
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What is the biodegradability of Biodiesel?
Biodiesel has desirable degradation attributes which
make it the fuel of choice for environmentally conscious users. Studies at
the University of Idaho, compared the
biodegradation of biodiesel in an aqueous
solution to diesel fuel and dextrose (sugar). Biodiesel
samples degraded more rapidly than sugar, and were 95 percent degraded at
the end of 28 days. Normal petroleum based diesel fuel was only about 40
percent degraded after the same 28 day test period.
Blending biodiesel with regular petroleum based
diesel fuel also accelerates the blended fuel's overall biodegradability.
For example, blends of 20 percent biodiesel and
80 percent diesel fuel (B20) degraded twice as fast as petroleum diesel.
100 percent pure biodiesel degrades as fast as
sugar and a 20 percent blend will degrade twice as fast as petroleum based
diesel fuel.
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What are the
sources of vegetable oil as fuel?
Virgin
vegetable oil can be harvested from many oil feedstock plants like
soybeans, sunflower seeds, rape seeds, palm oil
and even some types of algae. Recycled vegetable oil from local restaurants
and other used sources are also a useful reservoir of renewable fuel for
diesel engines as approximately 4.5 billion gallons per year of used vegetable
oil is available in the USA.
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