This paper reviews specific methods used by Wood Group Gas Turbine Services for boosting power output and improving heat rate for existing industrial gas turbines. The methods employed allow operators to make the most of existing equipment as a cost-effective alternative to the replacement of a complete engine. The article summarizes experience with the service and uprate of General Electric Frame 6B gas turbines using the company’s Advanced Parts Manufacture (APM™) turbine parts. A comparison of output and heat rate before and after service allows estimates of the performance improvement for individual components and combinations of hot gas path parts. Such comprehensive upgrades can be implemented only in older generation gas turbines that are part of a model line which the original equipment manufacturer (OEM) has redesigned. An ideal example of such a gas turbine model is the General Electric Frame 6B series. Wood Group Gas Turbine Services has extensive experience in overhauling and uprating the complete range of Frame 6B gas turbines. The company’s replacement parts have been installed in all stages of the hot gas path both as complete sets and in stages in combination with OEM parts in neighboring stages. Examples of components which can be upgraded include: • Turbine vanes and blades; • Combustion Lines and transition pieces; • Heat shields / shroud blocks; • Seals and clearances. All of these can be installed to increase the engine firing temperature and improve performance. The performance data is corrected to ISO conditions to enable a fair and meaningful comparison. The different configurations employed for the overhauls also permit estimates of the contribution of the replacement parts to the overall improvement in performance. Design details of the advanced technology parts are described as needed to provide understanding for the improvements in engine efficiency.

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