Help - SRV lines sizes

[sheiko]

Hello,

I am currently in the process of sizing inlet and outlet relief valve lines. We are in detailed engineering phase but the isometrics are not yet available. However i am asked to issue asap the SRV data sheets with.
I would like to know if one could provide me typical equivalent length values for both inlet and outlet lines sizing? or other guidelines?

Thank you in advance

"We don't believe things because they are true, things are true because we believe them."
"Small people talk about others, average people talk about things, smart people talk about ideas and legends never talk."

 

[insult2injury]

Inlet should be sized for the maximum 3% pressure loss and located as close to the source as possible.

Outlet length must be at least the vertical distance to the roof plus 7-8 ft.

There is no way to give mildly accurate L/Ds without some understanding of the physical plant arrangement.

I2I

 

[tkdhwjd]

Pressure drop criteria are in API guidelines. You need to work with construction organization and find out where the SRV is going to be located and how they intend to route the piping (inlet and outlet), and then use some conservative judgement and calculate.

 

[sheiko]

Thank

I would need another piece of advice: some relief valves will dischage in flare header, at atmosphere and in a drain drum.

Could you please tell me the metodology, document to use, in order to perform flare header sizing namely? Is it related to outlet line sizing?

"We don't believe things because they are true, things are true because we believe them."
"Small people talk about others, average people talk about things, smart people talk about ideas and legends never talk."

 

[CMA010]

API STD 521. Also for guidance on determination of relief loads.

 

[JoeWong88]

API RP 520 PI & PII, API STD 521, DIERS project manual, etc... are good reference...

When designing flare header, following may have to be addressed :
- velocity
- rho x velocity^2
- back pressure
- noise level
- acoustic Induced Vibration
- two phase flow

As for PSV inlet and outlet, other than sizing... other aspect are important as well. Simple compilation in "Concerns & Recommendations on PSV INLET line" and "Few Concerns & Recommendations of PSV Discharge Tail pipe"

JoeWong
Chemical & Process Technology