Modérateurs : Rod, Modérateurs
Un fil dédié à l'évolution des stocks de produits pétroliers aux USA ? Bonne idée Gilles !un nouveau fil pour suivre l'évolution des stocks d'essence raffinée aux US
oui je l'ai signalé ici : http://www.oleocene.org/phpBB2/viewtopic.php?t=2416"Devenson"
Un des facteurs de déséquilibre est aussi l'utilisation d'ethanol à la place d'un autre adjuvant, utilisation qui va devenir obligatoire dans quelques semaines.
Sur ces sujets, voir le blog de Robert Rapier qui se présente comme un spécialiste du sujet.
:
http://i-r-squared.blogspot.com/
Par exemple, son article "The Future of E85" où il fait l'effrayante prédiction que la transformation du charbon en carburant liquide se fera principalement par l'intermédiaire de l'éthanol.
R. Rapier intervient également souvent sur theoildrum (je me sens souvent assez proche de ses analyses).
The image in the background is the derived probablity map from the observed "number of day of consumption" since 1991. Dark patches indicate more frequent values. The Current level is near (slightly below) the most probable value for this day of the year).
US fuel crunch worsens
Fri Apr 21, 2006 12:35pm ET
By Richard Valdmanis and Janet McGurty
NEW YORK (Reuters) - Dozens of gasoline stations from Virginia to Massachusetts ran short of fuel on Friday as suppliers struggled with a transition to a new anti-smog gasoline blend using corn-based ethanol as an additive, marketers said.
The disruptions, caused in part by a lack of trucks to move ethanol to supply terminals, comes amid an already severe spike in retail gasoline prices to near $3 per gallon as the cost of crude hits new highs.
"The situation here is chaotic," said Mike O'Connor, president of the Virginia Petroleum Jobbers Association, which represents gas stations in the state. He said his association is seeking a federal waiver to allow the sale of lower grade gasoline to ease the crunch.
Fuel marketers said there were reports of gasoline stations running out of fuel in areas of Virginia, Maryland, around Washington D.C., in Philadelphia, Pennsylvania, and parts of Massachusetts.
"There are a handful of outages being reported across the region, but they are temporary," said Catherine Rossi, a spokeswoman for AAA Mid-Atlantic. "The problem is waiting for the trucks to get to the stations."
AAA is the largest motoring and leisure travel organization in North America.
The U.S. government had warned in recent weeks that gasoline supplies could be disrupted along the East Coast and in Texas as the oil industry shifts to the new anti-smog blend using ethanol.
Gasoline producers had previously used additive MTBE to make reformulated gasoline, required at a third of the nation's pumps to combat air pollution, but are phasing the chemical out because of the risk of lawsuits after several states banned it for contaminating groundwater.
The problem with the replacement additive, experts say, is that ethanol cannot be shipped in pipelines because it absorbs water condensation in the pipes, and requires trucks, rail cars or barges for transport.
"Anywhere there is reformulated gasoline and MTBE there will be a problem," said Jeff Lenard, director of communications at the National Association of Convenience Stores.
A federal waiver allowing the sale of conventional gasoline, instead of the anti-smog blend, would make it easier for fuel suppliers to sell gasoline without the ethanol additive.
"We're patiently waiting to see if the state will make a formal request on our behalf," said VPJA's O'Connor.
The Petroleum Marketers Association of America, which represents stations selling about 55 percent of the nation's gasoline, said it was unaware of any other state associations seeking a waiver.
"We're hoping this situation will be short-lived," said Rolf Hanson, executive director of the Pennsylvania Petroleum Association. "We think it is unlikely the government will grant waivers for a transitional issue like this one."
Methyl tert-butyl ether (MTBE) is a chemical compound that is manufactured by the chemical reaction of methanol and isobutylene.
MTBE is produced in very large quantities (more than 200,000 barrels per day in the United States in 1999) and is almost exclusively used as a fuel component in motor gasoline. It is one of a group of chemicals commonly known as oxygenates because they raise the oxygen content of gasoline. MTBE is a volatile, flammable and colorless liquid that is relatively soluble in water. When in groundwater MTBE moves more quickly than other fuel components. (California Air Resources Board, 2004). MTBE has a typical odor reminiscent of diethyl ether, leading to unpleasant taste and odor in water. MTBE is used in organic chemistry as a cheap solvent with properties comparable to diethyl ether but with a higher boiling point and lower solubility in water.
MTBE has been used in U.S. gasoline at low levels since 1979 to replace tetra-ethyl lead to increase its octane rating and help prevent engine knocking. Since 1992, MTBE has been used at higher concentrations in some gasoline to fulfill the oxygenate requirements set by Congress in Clean Air Act amendments; however, since 1999, in California and other locations MBTE has begun to be phased out because of its health risk related to widespread groundwater contamination (California Air Resources Board, 2004). The Energy Policy Act of 2005 drops the federal requirement for oxygen content in reformulated gasoline [1].
:Health risks
MTBE is known to be a carcinogen[3] and to cause kidney lesions in animals. As an ether, MTBE acts as an emulsifier, increasing the solubility of other, harmful components of gasoline (for example, the known carcinogen benzene). It thus may increase the risk of contamination by other compounds. MTBE is biodegraded very slowly, remaining in water for decades or more. In addition some MTBE degrades in blood to the associated alcohol, with a greatly increased residence time. The prolonged presence of this alcohol derivative is not fully understood.
Industry advocates of MTBE contend that it has little effect on humans, although its manufacturers did not test it for its effects on human health before introducing it as an additive. As of today, researchers have limited data about what the health effects from ingestion of MTBE. The Environmental Protection Agency (EPA) has concluded that available data are not adequate to estimate potential health risks of MTBE at low exposure levels in drinking water but that the data support the conclusion that MTBE is a potential human carcinogen at high doses. [4]
MTBE often ends up in drinking water, e.g. when fuel storage tanks leak near populated areas. Aside from health risks, MTBE negatively affects the taste and odor of drinking water, even at very low concentrations.