2 PSV's - 2 Vessels but 1 flame arrestor
2 PSV's - 2 Vessels but 1 flame arrestor
(OP)
I have 2 vessels that I want to tie together to go into a flame arrestor. During operation one vessel is at high pressure and the other one is at a low pressure.
Say if the current PSV outlet is 4", can I run 4" pipe to tie them both into a 4" flame arrestor or do I need to upsize the line.
If so which line would need to be upsized? The common line before the flame aresstor?
Thanks,
Say if the current PSV outlet is 4", can I run 4" pipe to tie them both into a 4" flame arrestor or do I need to upsize the line.
If so which line would need to be upsized? The common line before the flame aresstor?
Thanks,





RE: 2 PSV's - 2 Vessels but 1 flame arrestor
Best regards
Morten
RE: 2 PSV's - 2 Vessels but 1 flame arrestor
Relief valve discharge piping should be sized to limit built-up back pressure at the relieving valve and super-imposed back pressure at all other valves in the system. The limits on back pressure are a function of the set pressure of the valve and the type of valve (spring operated, balanced bellows, pilot).
Because of the limit on super-imposed back pressure, usually high and low pressure relief systems are kept separate. If they are tied together at all, it is usually immediately upstream of the vent (or vent scrubber, if you have one).
A good source of information is API RP 520 & 521.
Andy
New Orleans, LA
Petronyx Consulting Engineers, LLC
http://www.petronyx.com
RE: 2 PSV's - 2 Vessels but 1 flame arrestor
Ken
RE: 2 PSV's - 2 Vessels but 1 flame arrestor
Best regards
Morten
RE: 2 PSV's - 2 Vessels but 1 flame arrestor
N2, quenching steam, etc. are a much better way to go. Torisoidal ring (sp.) on the outlet to remove sharp-edged exit.