Shearing bolts of the fixation of the coupling between the turbine and the generator (09 MW)

[ismail06]

Bonjour

In the new gas treatment plant located in Algeria (JV), the first gaz was exported in the mid of December 2017) , two weeks ago from now , during the operation of the Solar turbine Generator it was happened a serious problem for two machines (09 MW by machine), that was the shearing bolts of the fixation of the coupling between the turbine and the generator
The investigation is ongoing to find the real causes of this failure by the Client /Contractor
May be someone met the same problem in the past that could give me his feedback about an idea about the failure , causes and the solution implemented to solve this problem definitely

Thank you in advance for your feed back

Best Regards

Djamel

 

[12345abc6ttyui67]

What size / grade / number of bolts? How are they arranged? What torque is applied through the coupling?

 

[drawoh]

ismail06,

Do you have photos?

--
JHG

 

[racookpe1978]

Have you contacted your Solar Turbines representative/technical assistance? Do that immediately!

For a coupling failure within two months of startup, you should not be tearing apart the unit without their representative present, or they will resist assuming the warranty cost.

 

[MotorCity]

A few questions....

What led you to believe it was shear failure? Why not failure in tension?

Any chance it is fatigue related?

Any chance temperature played a part?

 

[EdStainless]

following up Racookpe's comment, they were the bolts provided by the supplier and you have documentation of how they were installed?
I wouldn't touch it without a rep on site.
This could be serious (alignment, balance, and so on).

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[rb1957]

you forgot litigation

another day in paradise, or is paradise one day closer ?

 

[berkshire]

ismail06
Obtenir le représentant fabrique des turbines Solar la sur le site avant de vous toucher a rein sans eux il vous annulera cette garantie.
B.E.

You are judged not by what you know, but by what you can do.

 

[ismail06]

Good Afternoon
Thank you for all
The plant is under the epccs contractor and the vendor is coming after tomorrow in aim to do the investigation.
The contractor team replaced the broken all bolts of those GTG and both are in operation.
My intention of the post of this problem is someone met a similar problem and could give us his feedback

Best regards

 

[12345abc6ttyui67]

That entirely depends on what caused the issue. Suggest you provide more info.

 

[BrianE22]

Some good info here:

thread404-435953

 

[FreddyNurk]

BrianE22, that's a recursive link, you've posted the link to this thread.

EDMS Australia

 

[CouplingGuru]

ismail06,

With out photos it is pretty hard to diagnose the problem. However, a sheared bolt is 99% of the time due to over torque. The question is did you actually have a shear failure, with out pictures that will be tough to diagnose.
One thing I would definitely look into though is thermal growth, That can be incredibly destructive to couplings not properly selected. Again this is just speculation at this point, we really need some photos of the failed parts prior to disassembly. It is like a crime scene, don't disturb it until it is properly documented.

When it comes to couplings we are always here to help.

http://WWW.PSCCOUPLINGS.COM

 

[TheTick]

Cheap counterfeit bolts is a possibility.

 

[JJPellin]

If this happened in my plant, my first suspicion would be a problem with units when the bolts were torqued. Was the torque specified in English units and the torque wrench in metric units? Was the torque specified in inch-pounds and the torque wrench calibrated in foot-pounds? The other possibility would be a problem with thread lubricant. Was the torque specified for dry bolts (no lube), but the mechanics used Moly lube or some other never-seize?

Johnny Pellin

 

[racookpe1978]

You're focused on the bolts that hold the two coupling faces together shearing in two, but have not even mentioned EITHER (expensive, high-speed, precision rotating pieces of eqpt connected to their respective couplings!

"Something" stopped one or the other high-speed machines so suddenly that the bolts sheared. That sudden force, or massive but slow counter-torque, almost certainly damaged one or both of the compressor and gas turbine attached to the couplings that failed.

 

[Tmoose]

A general arrangement drawing and nicely detailed pictures of the failed bolts' fracture surfaces and the couplings would be useful to mull over until the sheriff arrives.

 

[byrdj]

given the limited information, and there was no mention of coladeral damaged one would expect from a "normal" coupling failure, could it be possible the turbine is equiped with a "shearing coupling"

If so, the reason for the overload would need to be identified

 

[ismail06]

Bonjour
See the attached the sheared bolt photos

Regards
DG

 

[CouplingGuru]

Thanks for the picture, It looks like there is groove machined in the middle of bolt shoulder? Then it failed right through the middle of that. We would need a close up picture of the fracture surface to actually see how it started and if it follows classic shear or if there is striations which would indicate fatigue from bending. The groove is concerning though, not sure of the reasoning behind that feature. would have to see a coupling drawing.


When it comes to couplings we are always here to help.

http://WWW.PSCCOUPLINGS.COM