Venting to Vapor recovery and venting to a flare

[v7042800]

My question has to do with venting a mechanical seal reservoir (plan-52) to flare vs. to a vapor recovery unit. Am I correct in assuming that the vru piping is at negative pressure, while the flare line is at positive pressure?

 

[georgeverghese]

Suction pressure to the VRU may be positive most of the time.

In any case, typically a VRU would receive feeds from continous venting sources - the flow from the seal pot on a plan 52 would be too small ( even during a typical leak scenario) to justify recovery.

 

[v7042800]

Thank you. I am most concerned with the pressure in the plan-52 reservoir. Wondering how much higher than atmospheric it woukd be when connected to a flare vs. vapor recovery system. Can you clarify?

 

[v7042800]

So I take it that both flare and vru lines are always at some positive pressure?

 

[georgeverghese]

Yes, safety considerations will require that the VRU suction be always kept positive to prevent air ingress into the compressor feed.