Hello everyone,
Hope this finds everyone well.
I am trying to install a relief valve on a fuel gas knock out drum to protect downstream gas turbine internal fuel gas skid. The below table presents the conditions.
Case Fluid State Relief Capacity lb/hr Relief State Orifice Size
Blocked Vapor 24284 130 "J", 1.287 sq.in
Discharge effective.
(isolated) fuel (Required 1.079 sq.in)
gas to turbine skid.
I have sized the PSV following API 520.
To facilitate the modification we have installed - during our recent turnaround, a tie-in with a blind flange on the flare header in preparation for connecting the outlet of the PSV. Since the flare header is always live, we cannot perform any hot work on it for 5 years and hence the reason for installing the tie in in advance.
My question is regarding the inlet and outlet pipe size to the PSV. The set pressure for this PSV is 310 PSIG and the site conditions favor a 2J3 PSV configuration. However, API 526 specifies the maximum set pressure for a 2J3 configuration is 285 PSIG. I want to know the implications on installing a 2J3 PSV with set pressure 310 PSIG.
The only implication I can think of is chattering. But then again, I do not see how the set pressure will affect this.
Appreciate your input