New TVA scrubber will mean cleaner air soon

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By The Staff



Technology that will reduce air pollution across East Tennessee is scheduled to start working at the Kingston Fossil Plant about a year from now.

“We’re on schedule to be on line in early to mid-November ’09; we’ll actually be scrubbing flue gas,” said Robert Rehberg, an official with the Kingston plant.

The scrubber will use a limestone slurry mix to clean the emissions of sulfur dioxide, a byproduct of the coal-burning process the plant uses.

The limestone mixes with water in the absorbers, reacting with the sulfur dioxide to form gypsum.

This will be pumped to the gypsum ponds.

The result will be that the emissions seen leaving the new shorter stack will be more visible — a big, white steam cloud — but that cloud will be cleaner.

“We’re going to be removing 95 to 98 percent of the sulfur dioxide from the flue gas,” Rehberg said.

The scrubber also is supposed to remove much of the mercury from the emissions.

“We want to make it clear we’re spending $500 million to clean up the environment. It is not a bad thing, but it is clearly a visible thing,” TVA spokeswoman Barbara Martocci said.

Officials had hoped to find a market, such as drywall, for the gypsum byproduct of the new scrubber.

The slowing economy has ground those possibilities to a halt.

“They (the marketplace) have more gypsum than they know what to do with,” said Martocci

By next fall, the south module, the first of the two absorber units that are part of the scrubber technology, will be online, scrubbing gas for half the plant.

Units six through nine will be sent through that system.

By April 2010, they expect to have the other absorber online, allowing for the complete scrubbing of the plant’s remaining units.

One look at the plant shows that there is much to be done.

Construction is still under way  with much of the construction material brought in by water on barges to the peninsula that is part of the plant property.

The absorbers themselves are done and the ductwork to the absorbers is closer to completion.

The electrical control building is complete and the transformers are up.

“They’ve started to build the silos,” Rehberg said.

Those silos will hold the pre-ground limestone for the scrubber process.

Some ductwork still needs to be done, including the addition of fans.

When the plant goes to the scrubber system, flue gas will begin leaving through the new stack created next to the absorber modules.

Of the two tall stacks currently used to release emissions, one stack will remain for a bypass stack if a situation ever arises that they need to bypass the scrubber modules.

“The north stack will be abandoned in place. The south stack is a bypass if we get in a situation,” Rehberg said.