For the PG917E gas turbine #7 unit of Shenzhen Nanshan Power Plant, there were fractures on the exit guide vanes and the compressor¡¯s 17th stage vanes, and therefore during the combustion overhauling it was found fallout broken vanes in combustion casing. Thus, according to the situations, the power plant adopted forced emergency overhauling for #7 unit. Our sub-branch, Nanjing Nanguang Power Equipment Installation Co., Ltd., carried on the overhauling project. With the efforts of overhauling staff of Nanjing Nanguang Power Equipment Installation Co., and under the energetic cooperation from the related leaders and technical personnel of Shenzhen Nanshan Power Plant as well as other overhauling staff involved, for almost 20-day¡¯s intense work, the emergency overhauling project was successfully fulfilled on Mar. 16, 2008.
The items completed in this project are mainly as follows:
1. Inspection of the fuel nozzles and replacement of the consumable parts.
2. Inspection of the combustion components, e.g. the crossfire tubes, combustion liners and transition pieces, etc. and replacement of 14 transition pieces, as well as all the seal bits on the side faces of the 14 transition pieces.
3. Inspection of the pressure surface on the 1st stage nozzles.
4. Major tasks of the project was to inspect compressor¡¯s 17th stage rotor blades, 17th stage vanes, as well as the compressor¡¯s EGV1 and EGV2, to make inspection and treatment of compressor¡¯s vanes from 11th stage to 17th stage, as well as the blade root adjustable gaskets of the guide vanes EGV1 and EGV2. To adjust the total clearance of the blade roots of the latter stages¡¯ vanes based on GE¡¯s specifications.
It was found in the #7 unit during emergency overhaul:
Broken compressor vanes
Dents on the vane grooves of the upper half casing due to attrition
The position of the broken vanes in the upper half casing
The compressor¡¯s 17th stage rotor buckets were marred
Cracks on blades after the flow outlet side was polished
translated by Yifei (checked by Donaldhwang)
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