ULSD Gelling - PeachParts Mercedes-Benz Forum

connerm · #1 02-10-2007, 01:01 PM

Someone sent this to me. Said it was from Wall Street Journal

Some school districts are blaming a recent federal mandate to switch to a
less-polluting diesel fuel for a spate of school-bus breakdowns that left
thousands of kids stranded and shivering in the extreme cold this week.

On Monday, when temperatures dipped below zero in East Allen County, Ind., 36 of
the county's 155 school buses started up fine but soon conked out because the
new fuel, thickening in the cold, clogged fuel filters. That same day, 30 miles
outside of Pittsburgh, Hempfield area schools had the same problem with 26 of
their 80 buses. Districts in Kansas and New England reported similar problems.

"The problem doesn't lie with the individual schools," says Lynda Kuchler,
transportation director for the East Allen County Schools. "The problem is with
the fuel."

In October, the Bush administration required diesel users, including buses and
trucks, to begin switching to ultralow-sulfur fuel to reduce air pollution. The
new diesel has 15 parts per million of sulfur, compared with about 500 parts per million
for the diesel it's replacing.

The problem comes during the refining process used to attain the ultralow-sulfur
ratio. That affects the naturally occurring wax in diesel in such a way that it
can cause the fuel to turn from liquid to gel more readily in cold temperatures.
Gelled fuel clogs the fuel filters and starves the engine, causing it to stop.

Environmental Protection Agency officials say there is nothing wrong with the
fuel. But it may have to be treated with special additives. Or engine warmers --
equipment that keeps the engine warm, usually using electricity -- may have to
be used, they said.

Margo Oge, director of the EPA's office of transportation and air quality, said
all diesel fuels gel in subzero temperatures. Both refiners and users have been
adding kerosene or other additives to diesel fuel for decades in such weather to
prevent it from thickening. "The only difference is when you add kerosene now,
it must be ultralow-sulfur diesel kerosene," Ms. Oge said.

The ultralow diesel rollout is the biggest change to fuel standards since the
country began removing lead from gasoline in the 1970s. Ms. Oge said that while
the changeover is going smoothly, part of the problem appears to be confusion
over the additives. Some school authorities said they weren't clear that special
additives or ultraclean kerosene had to be added. Ms. Oge also said some of the
refiners may not have used the proper mix of additives or ultraclean kerosene in
fuel provided to the school systems.

Patrick Carnicella, transportation director for Westmoreland County schools just
outside Pittsburgh, said bus problems caused schools to close Monday and
Tuesday, reopening after he figured out the problem. He calculated that the
additives cost about 37 cents a gallon, on top of the $1.93 a gallon the school
system pays for the ultralow diesel.

TheDon · #2 02-10-2007, 01:06 PM

All diesel fuel gels when it gets that low.. Those losers forgot to cut it with some kero.. Even if it is a winter blend a little kero will lower the gel point

pawoSD · #3 02-10-2007, 01:08 PM

Quote:

Originally Posted by TheDon

All diesel fuel gels when it gets that low.. Those losers forgot to cut it with some kero.. Even if it is a winter blend a little kero will lower the gel point

I agree, they just don't know what they are doing. Transportation workers in that type of climate should be well prepared to deal with events like that.

vstech · #4 02-10-2007, 01:29 PM

http://www.peachparts.com/shopforum/showthread.php?t=178850

#5 02-10-2007, 01:59 PM

The "treehuggers" just want to use the gelling as an excuse to push them towards natural gas or propane buses.

Blevinsax · #6 02-10-2007, 02:25 PM

Quote:

Originally Posted by ForcedInduction

The "treehuggers" just want to use the gelling as an excuse to push them towards natural gas or propane buses.

No, the real treehuggers would be pushing for them to run those buses on all that leftover pizza and french fry grease from the school kitchens! Now you want to talk about cold weather and gelling fuel......

!!!!

aklim · #7 02-11-2007, 10:57 AM

Not sure I follow. Why would it start up only to die out later? If it had gelled, it should have gelled to the point it doesn't start. The lines should have been gelled up so no fuel could go to the IP and all that, shouldn't it? Puzzling.

pawoSD · #8 02-11-2007, 02:35 PM

Quote:

Originally Posted by aklim

Not sure I follow. Why would it start up only to die out later? If it had gelled, it should have gelled to the point it doesn't start. The lines should have been gelled up so no fuel could go to the IP and all that, shouldn't it? Puzzling.

I agree, especially since the lines on the engine are more exposed to the cold and smaller than the main lines, which means they should gel even easier/faster.