DTE installs latest in pollution controls

Project at Monroe coal-fire plant nears completion

Above, John Schreiber of Monroe works in the control room. DTE Energy's coal-fired energy plant in Monroe is able to remove nitrous oxide and sodium dioxide with its new equipment.

THE BLADE/JETTA FRASER
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Above, John Schreiber of Monroe works in the control room. DTE Energy's coal-fired energy plant in Monroe is able to remove nitrous oxide and sodium dioxide with its new equipment.

Vacuum pumps are used at the Monroe plant to suck the water out of limestone slurry to create gypsum, which can be sold to drywall manufacturers.

MONROE — The end is in sight for a project to reduce pollution from DTE Energy’s Monroe Power Plant.

Several new types of environmental-control equipment have been added to the coal-burning plant in the past 10 years, part of a larger effort to reduce emissions and comply with upcoming federal mandates. The latest of these additions were revealed to reporters during a media tour of the plant Monday morning.

DTE Energy officials praised the recent installations, emphasizing the newness and efficacy of the equipment.

“Anything else right now is in testing or experimental,” said Frank Warren, DTE’‍s vice president of fossil generation.

The new equipment consists of two main devices: flue gas desulfurization systems, or FGDs, and selective catalytic reduction systems, or SCRs.

FGDs, which are also called “scrubbers” or “absorbers,” remove sulfur dioxide from the plant’s exhaust gases. They use a limestone slurry to react with and extract the sulfur dioxide, reducing such emissions by about 95 percent. According to Dan Casey, who supervises the FGD facility, the plant uses more than 550 tons of limestone each day to remove the sulfur gas.

The FGDs’‍ spent limestone can be sold as synthetic gypsum to drywall manufacturers. Such companies often prefer synthetic gypsum because its 95-percent purity can often exceed that of natural gypsum, Mr. Casey said.

At right, the concrete building which connects to the stack houses the ‘‍scrubbers,’ which use limestone to clean the exhaust Combined with a catalytic reduction system the process also removes mercury from the plant's emissions. A byproduct of the process is gypsum, which is the main ingredient in sheetrock.

SCRs, meanwhile, remove nitrous oxide from emissions by about 90 percent, said plant director Brian Rice. They work by exposing the gases to a catalyst, creating a reaction that produces nitrogen and water.

The ammonia-based SCR catalyst is made “on demand” at the Monroe plant, according to Mr. Rice. He said producing ammonia on-site improves safety and makes any potential crisis easier to manage.

The Monroe plant is the first facility in Michigan to operate both FGDs and SCRs in tandem. Working together, the two devices also decrease mercury emissions by up to about 90 percent.

The physical FGD complex cost $500 million to build, Mr. Rice said, and is part of a $2 billion investment the company has made in environmental-control equipment.

DTE Energy, formerly known as Detroit Edison, is a Fortune 300 company with approximately $24 billion in assets.

Contact Marissa Medansky at: mmedansky@theblade.com or 419-724-6368.