Converting a power plant from coal to natural gas is a long, complex undertaking. Dawes Rigging and Crane Rental, part of the ALL Family of Companies, brought its expertise to some of the detail work taking place in the conversion at Valley Power Plant in Milwaukee.
The plant generates electricity for the municipal power grid, produces voltage support for downtown Milwaukee and also supplies steam heat to more than 400 district energy customers, covering nearly two square miles of downtown. The conversion to natural gas was completed in 2015, but related work has continued for much of the past two years.
Most recently, ducts that once routed flue gas away from the boilers had to be demolished, removed, retrofitted and replaced. Gasbased power plants have different flue gasflow needs compared to coal-based plants, and the new ducts reflect this reality. Better suited to the natural gas environment, the new ducts weigh more than 15 tons each.
Prior to the project, Dawes Sales Manager Joe Ruddell put together a 3-D lift plan. Starting with an overhead satellite image of the plant's footprint, Ruddell layered on computer- aided illustrations detailing each phase of the work to be done. He worked closely with the plant's maintenance contractor, Day & Zimmerman, who knew how to navigate the tight job space in the midst of buildings, chimneys and silos.
In all, Dawes provided a total of three cranes for the project: a Grove GMK6250L with a 250-ton capacity, a 236-foot main boom and a 72-foot jib; a 550-ton Grove GMK7550 with a 115-foot main boom, 185-foot luffing jib, megawing system and 352,700-pound counterweight; and a 95-ton Grove GMK5095 with a 196-foot main boom and a 56-foot luffing jib.
Beginning on the west side, the GMK6250L was used to remove existing steel and ducts. Next, the GMK7550 was called upon for the critical work of setting the new ducts. Complicating matters was the fact that the ducts could not be placed in smaller sections and instead had to be lifted as single pieces. This nearly doubled the weight of each lift.
The process was repeated on the east side of the plant, with the GMK5095 standing in for the 6250L. Its 165-foot reach was deemed a better fit for this phase of the work. Finally, the GMK7550 returned to complete the placement of the new ducts.
"This project demonstrates the value of detailed pre-planning," said Brian Schauer of Day & Zimmerman. "Through a coordinated team effort, the project was completed smoothly."
The ALL Family of Companies is an industry-leading privately owned crane rental and sales enterprise in North America, with 37 branches operating under the ALL, Central, Dawes, Jeffers and ALT names.
For more information, visit www.Allcrane.com or call (800) 232-4100.
