I am doing system in which 2 PSVs (open to ATM) are installed on header (6”) which is coming from 30m height reactor nozzle to scrubber which is installed @ 15 m level.
Psvs are installed directly above header on the reactor platform (independent, not supported from reactor)
1) In order to qualify nozzle loads of reactor I need to give spring to this header.
Is it right to give spring to the inlet psv header?
But I am not finding any other option to it.
2) Please confirm the forces and location of the forces, I have applied.
Set 1
Vertical upward force at psv:
F1 =W²RT/(gPsA)
Horizontal Force @ psv opposite to outlet
F2= DLF * W√ (kT/(k+1)M)/366
Set 2
Downward force @ elbow
F2=DLF*(Wsqrt(kT/(k+1)M)/366+(Pt-Pa)*At)
At : Flow area of tail pipe at tip
Pt :Pressure at Tip
Ps: Set Presuure
A: orifice area
Other terms are as in API520.
These two sets I have applied in two different cases .
3) Even I am not able to qualify nozzle loads at PSV pop up condition in set 1 forces as upward force at psv F1 is causing excessive moment @ reactor nozzle.
I can’t restrict this upward force by giving hold down support to psv inlet as support can’t take thermal upward force for 30m expansion, even it will fail in expansion.
I am thinking of relocating psv from the platform to far away from reactor so as it will not have any effect on nozzle loads.
4) Inlet temperature is 225 C. What should we consider outlet temp?
I have considered both, 225 C and 21 C. But this seems to be too conservative.
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-Prashant