http://phys.org/news/2015-05-downside-biodiesel-fuel.html
[Couldn't possibly be the cleaning action of biodiesel in a vehicle with
years of petro-crap in fuel system. Not enough info in the article to
know, and lots of mythology re-cycled. Of course, if you were a
university prof looking for grant money, no point in looking at what
others have already learned when you can redo it all from scratch.
images in on-line article]
May 5, 2015
The downside of biodiesel fuel
The oil industry believes biodiesel is not to blame for problems that
Norwegian car owners are experiencing. But the nature of the fuel means
that it has to be handled differently than regular petroleum-based
diesel, a Norwegian researcher says, especially in colder climates or if
it is stored for longer periods.
Can diesel made from a biodiesel blend be blamed for clogged car filters
and nozzles, reduced or lost engine power and costly visits to the
garage by Norwegian car owners? No, says the oil industry. But Professor
Terese Løvås from the Norwegian University of Science and Technology
(NTNU) doesn't want to dismiss biodiesel concerns so easily.
"We know that biodiesel behaves differently than petroleum-derived
diesel. Biodiesel is a 'living' substance that can change and
deteriorate over time. This can create problems that are not addressed
adequately by the current European Union (EU) product standards. We may
need to review all the relevant standards, and look at what needs to be
done to prevent these problems," says Løvås, from NTNU's Department of
Energy and Process Engineering.
All auto diesel fuel sold in Norway contains as much as 7 per cent
biodiesel. The blend is intended to help reduce CO2 emissions, because
in principle biofuels are climate neutral. The biodiesel/petrodiesel
fuel blend requirements are based on EU product standards that stipulate
detailed fuel characteristics under various conditions.
Clogged filters
However, Norwegian car owners regularly report that they have problems
where biodiesel is suspected to be the cause. Following a sharp increase
in clogged diesel filters a few years ago, the British Department for
Transport asked the oil industry and regulatory authorities to solve the
problem. Auto filters became plugged by a waxy substance in cold
weather, and cars lost engine power. The BBC reported that the biodiesel
additive was the probable cause of the problems. A possible explanation
was the use of recycled cooking oil, which clumps readily in the cold.
The Norwegian television programme "TV 2 hjelper" reported the woes of a
car owner who earlier this winter struggled with repeated engine
problems and expensive repairs. The auto repair shop said that her car
could not tolerate diesel with the biofuel additive. The program also
interviewed a repair shop owner who said his shop serviced one to two
cars a week that had clogged filters and nozzles, probably caused by
biodiesel.
A familiar problem
According to Løvås, we don't know the full extent of the problem or how
much it has increased since biodiesel has been blended into petrodiesel,
but it is quite clear that it is a growing problem. "It's a well-known
issue among researchers and the subject of a lot of research," she says.
The main problem is that biofuels are less stable than petrodiesel, and
they deteriorate over time. Light, temperature and humidity increase the
rate of deterioration.
"Biofuels contain oxygen compounds, which can lead to oxidation if the
fuel is not processed and stored properly. The fuel then forms waxy
substances that can clog filters and nozzles," says Løvås.
The EU product standard EN590 summarizes the product requirements for
diesel fuel. The standard contains detailed requirements for cetane
numbers (corresponding to octane in gasoline), density and viscosity,
for example. Scientists, governments, engine manufacturers and oil
companies have collaborated to develop and periodically update the
standard over many years.
Standards inadequate
Løvås believes that the current diesel fuel standard does not adequately
address the problems that stem from biofuels changing over time.
"Right now, there are clear requirements for the fuel quality when it
leaves the production site. Perhaps we also need standard requirements
for fuel storage and handling, for example how long the fuel can be
stored, and under what conditions, without changing character," she says.
But more tests cost more money, as do technical measures such as extra
fine filtration to remove wax particles before filling the tank with fuel.
"If new requirements are imposed on oil companies, they want be sure
that the new demands solve the problem. More research is needed to be
able to say for sure what the cause of the problem is," says Løvås.
"Biodiesel is safe"
The Norwegian Petroleum Institute (NPI) represents companies that sell
petroleum products, gas, electricity and bio-energy in Norway. NPI's
Secretary General Inger-Lise Nøstvik, who graduated with a chemical
engineering degree from the Norwegian Institute of Technology, NTNU's
predecessor, is puzzled by the assertion that biodiesel fuel blends are
causing problems for car owners.
"NPI members account for 98 per cent of fuel sales in Norway and sell
nearly 3 billion litres of diesel annually. Questions about problems
with fuel grades are few and far between," she says.
"It's obvious that some biodiesel components solidify faster in extreme
cold. But there are big differences between various components. The fuel
sold in Norway meets the EU product standard and official requirements
for fuel quality. In addition, the diesel fuel sold in the winter is
called arctic diesel, which can withstand extreme cold. Diesel fuel,
both with and without added biodiesel, meets this requirement," says
Nøstvik.
She notes that engine manufacturers and oil companies are collaborating
on developing the European diesel standard. The Norwegian Petroleum
Institute is also involved with this ongoing effort.
New requirements may mean that biofuel must provide real reductions in
carbon emissions, and that production of the fuel will not compromise
biodiversity or displace food production.
The current product standard allows for the incorporation of up to 7 per
cent biodiesel, and Nøstvik says that she does not know of any imminent
plans to increase this limit.
Perishable goods
The Norwegian government increased the blending of biodiesel from 5 to 7
per cent in 2009, and increasing this percentage further is a political
objective. The transport company DB Schenker in Norway tried it a few
years ago, when biodiesel was free of fuel surcharges.
Einar Spurkeland, Communications Manager at DB Schenker in Norway says,
"In 2007, we pioneered running cars on B30, i.e. a blend of 30 percent
biodiesel. That led to many people having to rebuild engines and replace
hoses and nozzles. Some people also experienced problems at very low
temperatures."
The high percentage of biodiesel also reduced fuel stability. "The more
life there is in the fuel, the shorter its lifespan. B30 diesel had to
be treated like perishable goods," says Spurkeland.
The trial run with B30 was short-lived. That same year a tax on biofuels
was introduced, and with that the motivation dropped off.
Faith in biofuels
Environmental regulations for biofuels have intensified greatly in
recent years. The so-called sustainability criteria require that the
biofuel must provide tangible reductions in CO2 emissions, and that
production of the fuel will not affect biodiversity or displace food
production.
Stricter environmental and technical issues notwithstanding, Løvås has
faith that biofuels will remain an important element in the mix of
climate solutions.
"These are challenges that must and will be overcome. If the EU is to
achieve its goal of a renewable energy share of 20 per cent by 2020,
wind and sun are not enough. Biofuels must also be part of the equation.
Within parts of the transportation industry, especially heavy transport,
I cannot imagine options other than biofuels," says Løvås.
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