SST-300 Siemens Industrial steam turbine, Service & trouble shooting by Energetic

SST 300/GE 40 A 28 MW Siemens*

*Energetic nv has no agreements or any relationship with the original equipment manufacturer

Background

An industrial steam turbine in a Pulp mill was suffering from vibration problems at higher loads and the client was forced to limit their power output in order to prevent trip from vibrations. A lot of investigations had been conducted by other parties in the past without success.
Energetic was consulted to perform a trouble shooting. The analysis of trend data, facts and observations was remarkably innovative for the customer. Vibration measurements were performed under different loads and spectrums were assessed and evaluated by the energetic experts.
The possible cause came to light thanks to the extensive knowledge and experience of the energetic experts.
The trouble shooting activity of energetic is renowned for its resolving power. We are known for our in-depth technical knowledge and experience of the many projects already carried out (see our reference list : https://www.energeticmachinery.com/en/reference-list).

Outcome

It was concluded that the guide blades, for regulating the pressure in the low pressure part of the turbine, where the cause of the vibrations.
As soon as the power reaches the level to open the guide vanes the vibrations started to increase substantially, till installation tripped.
Energetic proposed to open the turbine casing for a closer visual inspection. Simultaneously Energetic prepared a calculation model in case simulation calculations has to be executed.
This inspection resulted in a visual proof of the problems with the intermedium guide vanes.
Inside the turbine we found that bolts and bolt springs was damaged and had broken off. The reason for this is because of sudden expansion of steam during commissioning or shut down. Slamming the guide vanes causing the bolts to brake. This later escalated the damages on several positions.
The rotor was also found damaged at the first stage seal strips.

Solution

Energetic shipped the rotor and damaged parts to their workshop at Stekene for repair. Seal strips was replaced in the workshop and reverse engineering was done on the bolts and springs in order to be replaced. Thanks to the resources of Energetic and in-house expertise, the repairs and could be executed immediately, minimizing the down time for the customer. Seal strip raw material is always kept on stock and manufactured tailor made for each turbine. Making it possible for to manufacture strips for any turbine. A material scanning was also made to see if improvements could be implemented on that aspect. That theory was true and the new parts was produced in a material with better mechanical properties for this application.
After a The total down time of 3 weeks the turbine was started back up again with stable and safe vibration levels also at higher loads.

This is a typical 360° service example offered by the Energetic team