After more than three years of planning and highly choreographed work, crews on the job to complete the dry flue-gas desulfurization environmental upgrade project of Northern Indiana Public Service Co.’s (NIPSCO) Unit 12 have the spring 2016 deadline well in sight.
The project, located in Michigan City, Ind., on Lake Michigan, comes with more than the usual challenges, none more so than space constraints and wild weather conditions.
“We have a very small footprint,” said Clint Jolliff, project manager with major projects. “The property is bounded by the lake on the north, the creek on the east and there is no room for expansion on the west. We had some limitations.”
The $250 million project is designed to bring the coal-fired generating plant into compliance with the 2010 NIPSCO/EPA Consent Decree, the Cross State Air Pollution Rule and (CSAPR) mercury air toxics standards.
To do that, crews are installing a circulating dry sorbent (CDS) flue gas desulfurization system (FGD).
“This is a dry scrubber, meaning we don’t have the large water use and discharge that the wet systems have,” Jolliff said. “It uses pebble lime, run through a hydrator and injected into two absorbers. All the flue gas will run through the FGD through two absorbers. The lime is injected into the absorbers and comes into contact with the gas resulting in a reaction between the lime and various pollutants. The flue gas is then put through a bag house which is comprised of 14,200 six-inch diameter, 30-foot long bags. The scrubber removes pollutants, such as sulfur dioxide, and particulate matter.”
Before work began in October 2012, NIPSCO held numerous planning meetings with vendors. Because the footprint on the job site is so tight with little area for fabrication and assembly of components, they selected an area 20 mi. (32 km) away at the Port of Indiana to have the project materials delivered to by truck.
“We asked all of the vendors to provide the components in their largest truck shippable pieces and deliver to the ports of Indiana,” Jolliff said. “We wanted them as large as we could build them to avoid to the need to have permitted loads for the truck deliveries. We just wanted to make it as seamless as possible.
“We leased two barges. The pieces that were fabricated at the Ports of Indiana site were put onto Goldhofers to transport to the dockside. The components were then loaded on the barge for transport on Lake Michigan and offloaded by the Kobelco 600 onsite at the Michigan City Generating Station. These components consisted of duct work, absorbers and the bag house modules.”
Due to the small footprint of the project site, the crews are challenged with a vertical job site, stacking much of the manpower on top of one another. That meant efficiency was critical.
“We have about 14,000 yards of concrete on the job,” Jolliff said. “We put in 1,206 friction piles which are 18 feet diameter and 70-feet long, which provides the necessary support for the foundation. There is approximately 3,000 tons of structural steel and about 163 miles of cable.”
Adding to the complexity of the project is the constant changing, largely unpredictable weather.
“Being on the lake, we experience a lot of challenging weather conditions,” Jolliff said. “We have a lot of wind days that shut down our crane. Then, there’s the lake effect snow along with the wind and this year, a lot of rain days. Even if you get a clear day, we can’t lift if the wind picks up.”
Other equipment on the job includes a couple of 4100 Manitowocs, man baskets, scissors lifts and cherry pickers. They originally built a crane pad for a Manitowoc 21,000, but later determined they didn’t need one quite so big. There are currently 300 skilled tradesmen on the job with the number expected to grow to about 350 before the project is completed.
Because of the location of the unit, environmental considerations were especially important, and significant efforts are being made to help ensure that all the standards for environmental controls are met.
“NIPSCO’s generating station is set right on Lake Michigan,” Jolliff said. “And, it is right next to Trail Creek. Just past our property line, within 50 yards, is the water. So, it is important that our environmental team plays close attention to ensure we meet all the standards, which includes the location of silt fencing, condition and location silt socks, making sure we keep the roads watered, making sure our water run offs are going in the right direction and more.”
The newly compliant Unit 12 must be in service by April 2016. But for the most part, the unit will remain on line during construction.
“The only time it will come off is during the fall outage,” Jolliff said. “We have to tie in the duct work, and it will be off line during that time.”
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