This view shows the base of the new stack (right) and one of the new scrubbers, called a jet bubble reactor (center). The old stacks, one of which can be seen at the left of the frame will remain standing, but will no longer be used once the new system is completely online later this year. (Staff photo by Ken Ritchie/kritchie@madisoncourier.com)
This view shows the base of the new stack (right) and one of the new scrubbers, called a jet bubble reactor (center). The old stacks, one of which can be seen at the left of the frame will remain standing, but will no longer be used once the new system is completely online later this year. (Staff photo by Ken Ritchie/kritchie@madisoncourier.com)
The first stage of the Indiana-Kentucky Electric Corporation's $670-million pollution-control project is now up and running.

Plant officials announced this week that one of its two new flue gas desulfurization scrubbers began feeding exhaust gas to produce cleaner emissions.

The scrubbers are said to decrease sulfur dioxide emissions by up to 98 percent. The technology reduces the vapor temperature leaving the stack while it increases the amount of water vapor emitted.

The Clifty Creek plant has six 217-mega-watt units that will feed to two scrubbers - the second scrubber is scheduled to begin operations in May.

"The employees of Clifty Creek are pleased that the system is in service and cleaning the air for ourselves, our families and our neighbors," Clifty Creek Manager Cliff Carnes said in a news release.

Sulfur is a natural part of coal. Pulverized coal is burned to heat water to produce the steam. The steam turns the turbines to make electricity. When coal is burned, the sulfur combines with oxygen and forms sulfur dioxide, a major pollutant.

The cleaned-up water vapor will go out the new, wider stack instead of the two thinner stacks, which will remain in place but not used.

The new stack is 982-feet high and 80-feet in diameter at the base and has two pipes from the scrubbers at the top.

The scrubbers use both chemical and mechanical processes to capture and remove sulfur dioxide from the combustion boiler's flue gas.

The sulfur dioxide in the flue gas interacts and is absorbed into a finely ground limestone slurry. Once dissolved, the sulfur dioxide reacts with the calcium in the limestone to form a solid compound.

A mechanical process removes the water from the slurry, and the resultant material, synthetic gypsum, is suitable for disposal at the on-site landfill, IKE said.

The result will be a constant white plume over the new stack, Carnes said, even during warmer temperatures.

"The new plume will have a white billowy appearance. Although it will look very different from the nearly clear plume from the older stack, it is mostly vapor and is a sign that the scrubbers are working effectively, providing cleaner air for everyone," he said.

The project began in 2007 but was postponed from 2009 to 2011 due to the economic downturn.

The construction has employed more than 900 local and regional workers. The new system requires 30 additional full-time workers at the plant.