Flex Seal Retrofit | CCGT Boiler – 7FA.04 | Gas Turbine Exhaust Flex Seal Retrofit in the USA

Flex Seal Retrofit: In the original design the Inconel leaf seal connecting the exhaust diffuser to the HRSG inlet is very close to the end bearing support tunnel. DEKOMTE offers an innovative, integrated solution that gives clearance and reduces heat radiation, to protect the lubricating oil and instrumentation supplies.

Client: GE 7FA CCGT Power Plant

Flex Seal Retrofit Solution: With approximately 900 installed units generating around 150 GW of power across 12 countries worldwide, GE’s 7F gas turbine has established itself as an industry benchmark. Its popularity is attributable to proven reliability, exceptional performance, and substantial economic advantages. Designed to meet the rigorous demands of modern power generation, the 7F turbine delivers not only impressive power output but also superior operational efficiency, which translates directly into increased profitability and sustainability for power providers.

One of the key strengths of the GE 7F gas turbine is its remarkable reliability. With a documented reliability rate of 98.6 percent, it significantly exceeds the industry average. This heightened reliability means operators can rely on the turbine for an additional five to six days of operation annually compared to less reliable systems. Such an increase in operational days directly impacts revenue streams and reduces downtime costs, significantly boosting the financial efficiency of power generation facilities.

The exceptional reliability of the 7F turbine also translates into reduced maintenance needs, lower operational expenses, and increased predictability in maintenance planning. By decreasing unscheduled downtime, plant operators can plan routine maintenance proactively rather than reactively, leading to optimized workforce management, streamlined operations, and reduced overall maintenance expenditures. Furthermore, the superior availability of the GE 7F gas turbine strengthens the stability of energy supplies, benefiting not only power providers but also end consumers, who benefit from consistent and uninterrupted power delivery.

Complementing the technical excellence of the GE 7F turbine, DEKOMTE offers an innovative Flex Seal Retrofit solution designed specifically to enhance its performance and operational longevity. Traditional sealing systems in gas turbines are subject to significant stress and environmental challenges, including extreme temperatures and vibrational forces, which can lead to efficiency losses, increased thermal wear, and elevated maintenance costs. Recognizing these common operational challenges, DEKOMTE engineered the integrated Flex Seal Retrofit solution, a system explicitly designed to mitigate these issues by effectively managing internal clearances and controlling heat radiation.

The DEKOMTE Flex Seal Retrofit solution provides a distinct advantage by significantly enhancing clearance management within the turbine system. By improving seal tightness, this retrofit solution ensures minimized leakage and improved turbine performance. The resulting reduction in internal leakage boosts thermal efficiency and reduces fuel consumption . Ultimately, GE’s 7F gas turbine, supported by DEKOMTE’s Flex Seal Retrofit solution, delivers unmatched operational advantages.

Total Output:

198 MW

Location: USA
Cycles: Cycling
Primary Fuel: Natural Gas

Original: Leaking Gas Turbine Exhaust Flex Seal

The standard GE 7FA exhaust diffuser had an Inconel leaf seal and a clip, bracket and plate system to transition from the hot casing exhaust, to a cold casing HRSG inlet duct. The design is not gas tight.

Regular problems caused by this design:
  • High temperatures in surrounding area caused by gas leakage creates damages to adjacent equipment.
  • The Inconel plates are inflexible and restrict movement.
  • Gas tightness is not achieved due to overlapping of plates.
  • Operation caused creasing and tearing, which results in increased gas leakage.

Solution: 3WA Inlet Frame with Outlet Cold Casing Integrated to Trough

In the original design the Inconel leaf seal connecting the exhaust diffuser to the HRSG inlet is very close to the end bearing support tunnel.

DEKOMTE offers an innovative, integrated solution that gives clearance and reduces heat radiation, to protect the lubricating oil and instrumentation supplies. The DEKOMTE solution integrates all adjacent insulation, is gas tight due to multi-layer fabric, has no reaction loads or forces and a steel frame design. This solution is highly flexible, minimises stress imposed to the exhaust diffuser and has a high cycling capability.

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