9 replies to this topic

[Komal shah]

Dear all,

I am working in Process department.I ahve a small doubt,can u please help me?

This is regarding high pressure boiler PSV.There is one regulation called Indian boiler regulation & boiler has to be designed according to IBR & has to be approved by IBR authority.

Now the question is there is one act says there should not be any isolation vale on PSV & each boiler shold be mounted with two PSVs.

If tehre is no isolationvalve then both the PSV should be designed with full rated capacity, because of that chattering problem can opccur,

Can anybody give me any option to avoid chattering.

Thanks,
komal
komal.maskaria@akersolutions.com

[Andrei]

Komal,

Usually the two PSV's (or more) on a boiler have different set pressures, and are not each of them sized for full rated capacity. API 520 Pt.1 is giving guidance on how to set the relief pressures.

Hi Komal,

I agree with Andrei. I am currently working on a project which consist of Once through boilers.
Boiler are provided with 2 PSV's, rated for full capacity together. They have staggered set points i.e.
set point of 2nd PSV is 3% higher than the first one.

Regards,
Gopal

[Qalander (Chem)]

Hi Komal,

I agree with Andrei. I am currently working on a project which consist of Once through boilers.
Boiler are provided with 2 PSV's, rated for full capacity together. They have staggered set points i.e.
set point of 2nd PSV is 3% higher than the first one.

Regards,
Gopal

Dear Komal shah,

It is usual customary to have the multiple PSV's set at pop pressures varying progressively 2~3% range.

Mostly these are not equal capacity since ;whenever the first one lifts load to be vented get decreased so is the case.

However if more than two PSVs then two out of three may have almost same capacity.Hope this helps
Regards
Qalander

[Komal shah]

Dear Qalander (Chem), gogisu, Andrei,,,,

Thanks for your reply,,,

once again i 'll gothrough the guidelines.

I have one more question is that in generally what we can do to avoid chattering problem in PSV??

Thx once again,

Regards,

Komal

[Qalander (Chem)]

Dear Qalander (Chem), gogisu, Andrei,,,,

Thanks for your reply,,,

once again i 'll gothrough the guidelines.

I have one more question is that in generally what we can do to avoid chattering problem in PSV??

Thx once again,

Regards,

Komal

Dear
This link is a good resource/guidance in general on chattering controls
http://webwormcpt.bl...vethe-ways.html
Hope this helps
regards
Qalander

[Komal shah]

Dear Gopal,

Its quite interesting site,

Thanks once again

Komal

komal.maskariya@akersolutions.com

[Shan Suresh]

Dear Gopal,

Its quite interesting site,

Thanks once again

Komal

komal.maskariya@akersolutions.com

To avoid Chattering of PSV, difference between the set pressure of PSV and max normal operating pressure of protected equipment should have more.......................

[JoeWong]

These three postings could be interesting :

• Isolation Valve Position when Spare PSV present
• Locked / Car-Sealed CLOSE PSV Inlet Isolation Valve ?
• Concerns & Recommendations on PSV INLET line

[Komal shah]

Dear Shan Suresh / JoeWong,

Thanks for ur veluable reply & efforts which you spent to solve my difficulties.

Thanks once gaian.

Regards,

Komal
komal.maskariya@akersolutions.com