Tag Archives: American Electrical Power

Coal scrubbers are corroding

Ohio pollution controls are showing wear after as little as a year.

Coal-fired power plants across the country are being checked for corrosion problems on billions of dollars’ worth of equipment that is supposed to cut air pollution. And the results from three power companies in Ohio show that the  scrubbers are corroding at a much faster rate than was expected.

Coal scrubbers – some 15 stories tall — spray a slurry of water and limestone into coal flumes to capture most of the pollutants before they’re released into the air. The scrubbers cost up to $500 million, and are supposed to last 25 years.

But Akron-based FirstEnergy discovered corrosion in three new scrubbers at its plant along the Ohio River. None of is older than a year.  American Electric Power also found corrosion at four plants in Ohio and West Virginia. And Duke Energy found it at its Southwest Ohio plant.

A national inquiry is now underway by The Electric Power Research Institute.

John Shingledecker is the senior project manager for the institute. He says he’s seen corrosion in as little as 11 months, and in wide variety of scrubbers.

“There was some initial thought that there was only one particular alloy that was being affected,” he said.

“But there are now different types of alloys, some that have been used in the past as well. And we’ve seen it in multiple designs and multiple manufacturers.”

Shingledecker says figuring out the cause of the corrosion could  take two years, and  in the meantime coal-fired power plants can use protective coatings or clay tiles to try to stop the corrosion.

But American Electric Power spokesman Pat Hemlepp says his company’s scrubbers are operating safely.

”We are working with the industry to address what happening. As far as an environmental standpoint, the equipment does what it’s supposed to do,” he said. “The equipment is taken down for maintenance routinely just like the plants are. And we’re doing whatever is necessary during those maintenance periods to take care of the corrosion issue. It’s not a safety issue, it’s not a health issue.”

Hemlepp says the cost of maintaining the scrubbers has already been calculated into customer bills.

The Columbus Dispatch reported this week that AEP negotiated a confidential settlement with, a contractor on the scrubbers to address corrosion at its central Ohio plants.

SOURCE: http://www.wksu.org/news/story/28895

‘Aggressive’ corrosion eats at power-plant scrubbers

When American Electric Power installed a pollution scrubber at its Cardinal plant along the Ohio River in 2007, it was supposed to last 25 years.

About a year later, an inspection found that something was eating through its steel walls.

“There were some areas in the tank vessel itself that ultimately corroded all the way through,” said Bill Sigmon, AEP’s senior vice president for engineering, projects and field services.

It wasn’t a freak occurrence.

The Electric Power Research Institute, which is funded by utility companies, is investigating reports of “aggressive” corrosion in scrubbers across the nation.

“Our findings, so far, show it’s fairly widespread through the industry,” said John Shingledecker, senior project manager in the research institute’s fossil materials and repair program.

Without a fix, corrosion threatens plant shutdowns and costly repairs, both of which could affect Ohioans’ power bills.

Scrubbers are key weapons in the fight to reduce pollution at coal-fired power plants.

They were installed to help meet a federal mandate that coal-fired power plants cut 71 percent of their sulfur-dioxide emissions by 2014.

They also were required by settlements FirstEnergy signed in 2005 and AEP agreed to in 2007 to end separate federal air-pollution lawsuits.

Central Ohio AEP customers already are paying for the scrubbers. State regulators permitted the company to increase base fees as much as 7 percent in 2009, 6 percent in 2010 and another 6 percent this year.

Estimates kept by the Public Utilities Commission of Ohio show the average Columbus residential electricity bill for the month of June rose from $87.90 in 2008 to $95.21 this year.

There are about 360 operating scrubbers at U.S. power plants. They are used mainly to catch sulfur dioxide, a key ingredient in the smog and soot pollution that plagues U.S. cities, including Columbus.

Research Institute officials are focused on 166 scrubbers installed since 2006.

As many as 70 are made of a type of stainless steel that appears particularly vulnerable to corrosion.

In addition to Cardinal, AEP found corrosion in new scrubbers at its Conesville plant in Coshocton County and at its Mountaineer and Mitchell plants along the Ohio River in West Virginia.

The company spent $1.7 billion to install five scrubbers at those four plants, said Melissa McHenry, a company spokeswoman.

Duke Energy found corrosion in two Miami Fort plant scrubbers in Hamilton County, which cost $365 million. Akron-based FirstEnergy found initial signs of corrosion in three new scrubbers at its W.H. Sammis plant along the Ohio River in Jefferson County.

“They became operational in January,” FirstEnergy spokesman Mark Durbin said.

It cost $1.8 billion to install scrubbers and other pollution filters there.

A scrubber can hold as much as 1 million gallons of lime slurry, a solution that captures sulfur compounds in hot power-plant smoke before it goes up the stack.

Although no scrubber has “failed,” utility officials say they want to know why some are corroding. Duke Energy spokeswoman Erin Culbert said the company, so far, has spent more than $5 million on short-term repairs.

“We do not want to be applying Band-Aids,” Culbert said.

Sigmon said AEP negotiated a confidential settlement with a contractor, to address corrosion at its Conesville and Cardinal plants.

Shingledecker said it could take as long as two years to identify a root cause of the corrosion and find a solution.

SOURCE: http://www.dispatch.com/live/content/local_news/stories/2011/07/10/aggressive-corrosion-eats-at-power-plant-scubbers.html?sid=101#story-continues