Zepco Expansion Joint Retrofit at Florida Power Plant

Challenge

At a power plant in Florida, the OEM joint design consisted of toed-in angle flanges with 90° corners and a composite belt bolted down with studs. This joint design had minimal internal insulation, resulting in high external temperatures radiating from the expansions causing heat related failures of wires in the area adjacent to the joint. Because of the high heat, the area around the joint had to have added protective measures to prevent accidental contact by personnel working in the area.

Solution

Zepco engineered a retrofit of a ZL-8000 GT expansion joint and frame, allowing for the joint to be shop-assembled in a frame design that uses standard nuts, bolts, and washers to attach the belt to the frame.

The gas turbine frame design also incorporated an additional internal insulation pillow with floating SS liner plates to match the internal insulation of the duct design-making for easy future joint replacement at a minimal cost compared to the OEM design. The radiant temperature around the expansion dropped from 600 -800°F to under 150°F.