Lube Oil Leakage from H2 Cooled Steam Turbine Generator Bearings seals

We have Alstom Steam Turbine capacity 400MW equipped with 02EA GE 9HA turbines in CCPP of capacity 1223MW commissioned in 2018. Steam turbine generator is H2 cooled.

There are leakages from STG bearing oil seals and we are searching for a root cause. Following are my questions

1. What is recommended Vacuum pressure inside lube oil tank as it is not mentioned in OEM manuals
2. Similar issue was reported at a similar site with same machine and configuration and was resolved by adding another line on return to increase the flow back to lube oil tank. It was done by OEM under warranty.
3. GE has not installed any vacuum gauge on lube oil tank? Is it part of their design or its does not has any influence that is why was not installed.
4. Vacuum was not adjusted since commissioning and this leakage issue was raised last year in Sep 2019. (one of the reason vacuum was not adjusted as it considered similar issue as on similar site which was rectified by adding an additional return line)

Kindly provide any technical detail to cater this issue.
 
We have Alstom Steam Turbine capacity 400MW equipped with 02EA GE 9HA turbines in CCPP of capacity 1223MW commissioned in 2018. Steam turbine generator is H2 cooled.

There are leakages from STG bearing oil seals and we are searching for a root cause. Following are my questions

1. What is recommended Vacuum pressure inside lube oil tank as it is not mentioned in OEM manuals
2. Similar issue was reported at a similar site with same machine and configuration and was resolved by adding another line on return to increase the flow back to lube oil tank. It was done by OEM under warranty.
3. GE has not installed any vacuum gauge on lube oil tank? Is it part of their design or its does not has any influence that is why was not installed.
4. Vacuum was not adjusted since commissioning and this leakage issue was raised last year in Sep 2019. (one of the reason vacuum was not adjusted as it considered similar issue as on similar site which was rectified by adding an additional return line)

Kindly provide any technical detail to cater this issue.
Hello ALL,
AAKHAN,

Without be able to check P&ID it would be difficult to get an overview of what is may be root cause analysis of the issue you describing.

What you mean by Vacuum was not adjusted since commissioning? ( even adding return line did not solve the problem)? can you confirm
Is your plant one of the 3 9HA plant in Pakistan (Balloki , Guddu, Bhiki) ? It sounds like it is ...
I know some dudes working on there.

What GE belfort ( GEEPE) /GE US / PAKISTAN is saying about that issue?

I can suggest you to check out these two interesting videos on H2 Generator seal oil system:

Do you get any alarm like Generator seal oil pressure low ...or other alarm related to the seal oil/lube oil system?

See this excellent slideshare ( decribing very well Seal oil sytem ):
https://fr.slideshare.net/SteveFord10/example-hydrogen-seal-oil-presentation

It will give you some tips/advice on this skid controls /monitoring.

That may give you some better overview, for better troubleshooting this issue.
Controls Guy25.
 
Thanks for the response. I think there is some mis-understanding. Let me clear my question again.

We have "Lube Oil Leakage" from Steam Turbine bearings oil seal at Balloki Site. The lube Oil returns to Main lube oil tank. The main lube oil tank is maintained under vacuum. Now following are the queries.

1. We do not have any recommended value from OEM to maintain in ST main lube oil tank. What is recommended value of vacuum?

2. At similar site, same bearing lube oil seal leakage issue was rectified by adding an additional line by OEM under warranty. We have wrote the same concern for our site but OEM has not responded yet.

3. The site was commissioned in July 2018 and this issue occurred in 2019 Sep. Is there any possibility that there is a physical damage on oil seal?

I hope i have cleared my questions.

And the above system video are very helpful for understanding H2 seal oil system. Thanks for sharing that.
 
Thanks for the response. I think there is some mis-understanding. Let me clear my question again.

We have "Lube Oil Leakage" from Steam Turbine bearings oil seal at Balloki Site. The lube Oil returns to Main lube oil tank. The main lube oil tank is maintained under vacuum. Now following are the queries.

1. We do not have any recommended value from OEM to maintain in ST main lube oil tank. What is recommended value of vacuum?

2. At similar site, same bearing lube oil seal leakage issue was rectified by adding an additional line by OEM under warranty. We have wrote the same concern for our site but OEM has not responded yet.

3. The site was commissioned in July 2018 and this issue occurred in 2019 Sep. Is there any possibility that there is a physical damage on oil seal?

I hope i have cleared my questions.

And the above system video are very helpful for understanding H2 seal oil system. Thanks for sharing that.
Thanks for the feedback!

I know that you pointed some questions on Vacuum for example....

But as far as I know there should be, specifications described on OEM O&M manuals.

My previous post was written for having a better overview (3D view) on the H2 Generator seal oil system .

That's all I can add for the moment,

Maybe somebody else, on this excellent forum, can add some notes.

ControlsGuy25.
 
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