Situation: A construction contractor was charged with installing a selective catalytic reduction unit (SCR) over an existing precipitator for a coal-fired power plant in the Southern United States. There was no room to place a conventional crane and even a super crane didn’t have the capability to reach over from outside the unit to assemble the reactor structure.
Action Taken: Becht Heavy Lift was contracted to perform a feasibility study and recommend a hoisting method for installing the reactor components. Heavy duty tower cranes were considered but lacked the capacity and reach to handle the heavy loads.
Results: Becht team came up with the idea of using an elevated platform to position a 660-ton crane directly above the existing structure. Hours of research went into confirming the capacity, reach capabilities and constructability of the crane. A preliminary design of the platform/tower structure ensured it would fit and could safely be erected in the limited space. The platform/tower footings turned out to be significantly smaller than a foundation for the heavy-duty tower crane.
The project had a very demanding schedule including heavy liquidated damages for missing the deadline. The heavy duty tower cranes could have done the job. However, they had limited capacity and could only make smaller, relatively light lifts. This method would have resulted in multiple, smaller lifts and would have required temporary support for the various truss components during assembly, thereby extending the erection time. The photo shows a completely assembled truss system, the supporting structure for the reactor, being lifted in one piece.
For comparison, a heavy duty tower crane is set up between the stacks (on the left side of the photo) and was used to lift miscellaneous parts and pieces. One can clearly see the advantage of the large crane.Contact