Colorado Technology Firm Joins with Xcel to Reduce Mercury Emissions
The Denver Post --Jun. 2
Jun. 2--Xcel Energy wants to have its fly ash and sell it, too.
If it works, Amended Silicates -- a joint venture of Jefferson County-based
ADA Technologies and Douglas County engineering firm CH2M Hill -- could get a
big chunk of a future mercury-control industry estimated at $2 billion to $5
billion a year, said Cliff Brown, ADA's president.
The first rules limiting mercury emissions from power plants are under review
in Washington and could go into effect in 2007 or 2008, Brown said.
"You never know, there may be mercury regulations coming down the pike,
and we just want to be ready," Xcel spokesman Steve Roalstad said.
Burning coal releases mercury, and limits were proposed because mercury can
cause neurological damage to children and fetuses. Exactly how dangerous the
metal is, and at what quantities, is a matter of scientific and political
debate.
Mercury already can be reduced using activated carbon, but the fly ash that
results is unstable in cold weather and thus unusable for road-building in most
places.
The new process uses a patented blend of sand and chemicals that is supposed
to act like a mercury magnet, sucking 80 percent of the toxic metal out of the
gas the plant spurts into the atmosphere.
During a three-week trial that began the week of May 17 at Xcel's Arapahoe
generating station in Denver, the mix is being blown into gas in the plant's
flues. The gas and ash then are spat out into "baghouses," filters
resembling gigantic vacuum-cleaner bags.
If all goes as planned, Colorado's air will get cleaner exhaust gas, and Xcel
will get ash that's stable enough to sell.
"We do think it's a promising thing," said George Offen, technical
executive for air emissions and combustion product use at the Electric Power
Research Institute in Palo Alto, Calif.
The institute is funded by utilities and is helping pay for the Arapahoe
tests but is an independent scientific voice with no allegiance to any
particular utility, ADA's Brown said.
Offen said the question isn't so much whether Amended Silicates' product can
absorb mercury but whether it can do so at an acceptable cost.
"That's a moving target because the acceptable cost is a function of the
competition, what other technologies are out there and available. And as time
goes on, people are coming up with other options," he said.
Fly ash sells for $15-$40 a ton, and 30 million tons are recycled in this way
each year nationwide, said Jim Butz, ADA's vice president of operations.
"Instead of having to pay to landfill the stuff, the utility gets a cost
benefit that they then pass on to ratepayers in the form of lower electricity
rates," Butz said.
The Amended Silicates blend should absorb just as much mercury as activated
carbon, Butz said. Untreated emissions contain 4-5 micrograms of mercury per
cubic meter of gas, while treated gas has about 1 microgram, he said.
Although all American utilities are helping pay for the Arapahoe trial
through their research institute dues, the formula will remain Amended
Silicates' property.
"If you took a sample and analyzed it, you could figure out what's in
there, but how you make it is a real art," Brown said.
ADA can make small batches of the substance at its facility in a Jefferson
County business park. Medium-sized batches come from another facility in Golden,
and for big orders, such as the ones used at Arapahoe, the company uses a plant
in Georgia.
"In the grand scheme of things Amended Silicates would like to build a
plant dedicated to making this stuff," Butz said.
ADA was founded in 1985 and has 33 employees, Brown said. Aside from the
Amended Silicates venture, the company is cooking up a suite of novel
technologies, including what it says is a better way to detect explosive
materials on people or luggage.
One ADA idea could make life sweeter for grocery shoppers: a label that
changes color when a piece of fruit is ripe.
The label's first application, likely one to two years away, would be on
pears, Brown said.
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