Letdown station 6

[Joud medo]

Hi
I am Utility Shift team leader and we have steam letdown station but one of the valves stuck opened and can not isolate it to hand over attemperator valve to maintenance , my question is Is there any technique to isolate the valve online ?

 

[shvet]

inlet/outlet and bypass valves?

 

[Joud medo]

The line is 18 inch , the valve is the main valve and there is no bypass

 

[shvet]

If there is no bypass then a process developer/designer considered that process should not operate in case of CV malfunction, correct? Why do you believe that developer/designer's reasons are not valid more? Why should a process be operated not as intended for?

Do you have an option to switch superheated steam to atmosphere and close CV's inlet valve?

 

[LittleInch]

Sameh,

How is anyone supposed to answer this when you have provided no sketch or drawing to show what the issue / valve is, but sometimes there is no option other than go back down the line and find an isolation vale and the de-pressurise the header and remove / replace the valve.

If the original designers wanted to save money by not putting in suitable isolation, then this is consequence.

But give us a bit of a clue please.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Joud medo]

Sorry for that, i tried to sketch it as P& ID is confidential , I want to isolate online steam line to remove athe attemperator as showing in the sketch
Note : i heared about AOGV isolation but not sure will be ok for 18 inch valve or not

 

[shvet]

i heared about AOGV isolation but not sure will be ok for 18 inch valve or not

You should contact a local contractor.

https://www.ik-worldwide.com/assets/AOGV/AOGV-presentation-december-2020.pdf

 

[Joud medo]

Thanks for helping

 

[georgeverghese]

Safety FIRST, Profit Second.
Tell your Operations Manager he has find some other less suicidal challenge to get his promotion.

 

[Joud medo]

It is not like that, plant is running and this job need total shutdown so we are searching for another solution to avoid total shutdown, our turn around will be in 2025!

 

[LittleInch]

What's wrong with the isolation valve?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Joud medo]

Full respect to all but this is the first time to me in thus forum, anyway the isolation vlave is not fully closed and want to remove upstream CV (attemperator) for maintenace but could not isolate it due to this passing

 

[pierreick]

Hi,
Consider this link:

https://www.linkedin.com/pulse/online-isolation-repairs-valves-pumps-kjetil-aamodt

Agree with George.
Pierre

 

[Joud medo]

Thanks Pierreick

 

[LittleInch]

Concentrate on the valve.

What type?
Is it closed and just passing or??
Are there no sealant injection points?
If a ball valve can you vent the ball enough to prevent passing of steam?
Have you stroked it a few times?
Any details?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Joud medo]

Hi littleinch
The valve type is gate valve
The valve is passing
Opened and closed many times but no improvment same passing
No seal injection point
This valve want to close it to remove upstream CV for repairing and no isolation for it , it is live with MPS header , need to avoid total shutdown

 

[0707]

Hot tapping can be a solution for your problem.

regards and good luck

https://www.google.com/search?sca_e...Uq6DBYQpboHKAB6BAgBEAI&biw=1366&bih=651&dpr=1

 

[Joud medo]

Hot tapping i beleive for small pipe not for large , our size is 18 inch !

 

[LittleInch]

Tried Furmanite?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Joud medo]

Is furmanite can isolate gate valve and remove the valve later ? After repair the defcted valve