When Duke Energy built its Flue Gas Desulfurization (FGD) project at the Marshall Steam Station, they contracted PCL to fabricate and install the ductwork, including the erection of the steel support structure, for three FGD units on four existing coal-fired boilers at the plant.
Due to the magnitude of the fabrication, the site constraints, and the scope and complexity of the lifting required to place the fabricated ductwork, the client required a contractor with significant experience in building large, complex utility projects. This fit PCL’s background, and the team fabricated 73 duct sections averaging 33 feet tall by 22 feet wide by 70 feet long, and weighing over 100 tons. The support structure for the ductwork required the erection of 2600 tons of steel.
Installation of the duct involved lifting sections from the fabrication area to a location on the opposite side of the plant some 700 feet away. This required the team to utilize a 2500-ton-capacity crane with 610 feet of main boom, 90 feet of jib, and 2.5 million pounds of counterweight. PCL performed these engineered lifts with no safety incidents and no impact to plant operations.
The fabrication and installation of the 5000 lineal feet of this massive ductwork required 46 miles (74 km.) of weld placement. The team’s innovative and efficient duct fabrication and erection prompted the client to recommend PCL for a similar scope at another utility’s FGD project.