Comment Log Display

Hello,

If you are not aware of this current (April 27, 2007) work going
on at Argonne National Laboratory, you ought to be.

http://www.anl.gov/Media_Center/News/2007/CMT070427.html

ARGONNE, Ill. (April 27, 2007) — A catalyst developed by Argonne
researchers could help diesel truck manufacturers eliminate
harmful nitrogen-oxide emissions from diesel exhausts.

The pattented technology appears so promising that multiple large
and small companies have expressed interest in licensing it and
working with Argonne researchers to scale up the technology and
bring it to market. Argonne researcher Christopher Marshall, one
of the technology's developers, believes there could be a
commercially available product within two to three years.

Nitrogen oxides — collectively called “NOx” — contribute to smog,
acid rain and global warming. Yet they are among the most
difficult pollutants to eliminate from diesel exhaust. For
example, many technologies that reduce NOx result in increases in
undesirable particulate emissions.

"For diesel engines, we envision manufacturers placing ceramic
catalytic reactors in the exhaust pipes, where they will convert
NOx emissions into nitrogen," said Marshall, who works in
Argonne's Chemical Engineering Division. Nitrogen, or N2, is a
harmless gas that makes up more than 80 percent of the Earth's
atmosphere.

"Our most promising catalyst for diesel engines," Marshall said,
"is Cu-ZSM-5 with an external coating of cerium oxide." Cu-ZSM-5
is a zeolite with copper ions attached within its micropore
structure. Zeolites are common catalysts in the petroleum
industry.

Those working previously with Cu-ZSM-5 and similar catalysts, he
said, found that they performed poorly at removing NOx from diesel
exhaust. They require temperatures higher than normal diesel
exhaust temperatures and don't work well in the presence of water
vapor, which is almost always found in engine exhausts.

With the help of the Advanced Photon Source at Argonne to analyze
the structure and performance of various catalysts, Marshall's
group at Argonne developed an additive that allows Cu-ZSM-5 and
similar catalysts to overcome these difficulties.

"Our new cerium-oxide additive," Marshall said, "is the
breakthrough that makes it work. When it's combined with Cu-ZSM-5,
the resulting catalyst works at normal exhaust temperatures and is
actually more effective with water vapor than without it. With a
lean fuel-air mixture, it removes as much as 95-100 percent of NOx
emissions."

Argonne's new catalyst also avoids the problems associated with
ammonia, which competing catalysts use as the reductant. The
Argonne catalyst uses the diesel fuel that is already on board
thereby requiring no additional tankage.

"Another type of technology is ammonia-selective catalytic
reduction, using a material called urea as the ammonia source,"
Marshall said. "Ammonia is toxic, and unless all of it is
converted during the process, whatever remains could be released
to the atmosphere. While some European diesel manufacturers are
taking the urea approach, U.S. diesel manufacturers are looking
for alternatives." Since a system using the new catalyst would not
require an on-board urea storage tank and uses the onboard diesel
fuel as the reductive material, the new catalyst is considered
safer and more energy-efficient.

Another alternative for U.S. manufacturers is the use of NOx
traps. These are platinum-based systems that work well if they
don't come into contact with sulfur, which is present in most
commercial diesel fuel. Since the Argonne-developed catalyst
contains no platinum, it is degraded far less by the fuel-borne
sulfur.

Marshall says the Argonne catalyst has been tested and performed
well with a number of diesel and diesel-type fuels, including
standard diesel, synthetic diesel, bio-diesel and JP8, which is a
jet fuel preferred by the military. Having performed well in these
tests, the next step is to subject the catalyst to engine testing.
This will take place soon at Argonne's Diesel Engine Test
Facility. Marshall expects these tests will show that in addition
to its other advantages, the Argonne catalyst has a greater life
expectancy than other catalysts currently on the market.

Marshall and his colleagues are also working with the Chemical
Engineering Division's fuel cell research group. Using a reformer
developed by this group could provide better fuel for the
catalyst, said Marshall. "Our catalyst already works well, but it
would work even better with the smaller hydrocarbons produced by a
reformer. Collaborations like this and access to Argonne's unique
facilities allow us to work together on projects in a way that
couldn't be done anywhere else."

Initial research on the cerium-oxide catalyst was funded by the
U.S. Department of Energy's Office of Energy Efficiency and
Renewable Energy. The catalyst was developed for chemical plant
emissions under a joint research agreement with BP. Research plans
call for expanded work aimed at both diesel and natural gas engines
and coal-fired power plants.

With employees from more than 60 nations, Argonne National
Laboratory brings the world's brightest scientists and engineers
together to find exciting and creative new solutions to pressing
national problems in science and technology. The nation's first
national laboratory, Argonne conducts leading-edge basic and
applied scientific research in virtually every scientific
discipline. Argonne researchers work closely with researchers from
hundreds of companies, universities, and federal, state and
municipal agencies to help them solve their specific problems,
advance America 's scientific leadership and prepare the nation
for a better future. Argonne is managed by UChicago Argonne, LLC
for the U.S. Department of Energy's Office of Science.

For more information, please contact Steve McGregor (630/252-5580
or media@anl.gov) at Argonne.