PSV Discharge Reducer 2

[davidysong]

Is it preferred that using Flat On Top Eccentric Reducer on psv discharge? Somebody disagree with me using concentric reducer on psv discharge.

Thanks!

 

[MikeHalloran]

I disagree with using _any_ reducer on psv discharge.


Mike Halloran
Pembroke Pines, FL, USA

 

[katmar]

I agree with MikeHalloran that unless you are using the reducer to increase the size of the discharge piping there is a problem with you installation. You have not given nearly enough information to rule out a concentric reducer.

Katmar Software - AioFlo Pipe Hydraulics

http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

 

[ione]

davidysong,
You've not made any reference to the code you are using, nor what the reducer is intended for. For instance ASME Section VIII, Appendix M-8 reports that discharge pipes shall be at least of the same size as the pressure relief valve outlet.

 

[davidysong]

I am sorry I should have provided more detial information. This PSV is dicharged into a closed system, reducer is to increase discharge pipe size.

Thanks!

 

[MikeHalloran]

Discharging a PSV into a closed system doesn't sound like a real good idea.


Mike Halloran
Pembroke Pines, FL, USA

 

[C2it]

Mike,

So far as I am aware, every PSV in offshore installations and in most modern refineries discharge into a closed collection system, then via a KO drum to a vent / flare.

 

[MikeHalloran]

If there's a vent, the system is not closed.

It probably doesn't matter. We don't know if the system under discussion is offshore, onshore, in a refinery, undersea, or airborne. We don't even know the state of whatever fluid comes out of the PSV, nor the state and pressure of whatever fluid the PSV is holding back.

I suppose we could guess that the fluid is not completely gaseous, because of the expressed concern about flat up/ flat down/ eccentric expanders, but beyond that, who knows?.





Mike Halloran
Pembroke Pines, FL, USA

 

[MortenA]

OK its a bit confusing i agree - under the assumption that its gas and in order to reduce the risk of having liquids that collect at the PSV nozzle and either freezes or causes corrosion i agree that an eccentric top flat reducer would be optimal (assuming its on the horizontal pipespool but i don't recall seeing this specified on P&IDs that i have come across.

 

[pennpiper]

MortenA,
Someone correct me if I am wrong but I do not think the orientation of an Eccentric Reducer is a P&ID comment issue.
The proper orientation of an Eccentric Reducer (no matter where it is installed) is the responsibility of a well trained and experienced Piping Layout Designer.

prognosis: Lead or Lag

 

[MortenA]

I would show if it was an eccentric reducer and i would show if it was top or bottom flat. But i wouldt show if the pipe it was attached to was horizontal or vertilcal. When its important i would show a slope (direction and inclination). There is no fixed rules for P&IDs except those that companies make up for themselfs.

 

[davidysong]

thanks for all replies.

MortenA, If there is a vent valve right after reducer, is it still prefered using an eccentric top flat reducer?