Dry gas seal venting

[rQuestionEngineering]

Is it economical to reclaim flaring from dry gas seal gas vent?
How is the ROI calculated ?

 

[rotw]

Vent goes to atmosphere / safe location.
Are you aware that the way the question is phrased, what you gonna reclaim is mostly inert gas or air with traces of hydrocarbons at best?

 

[rQuestionEngineering]

In was referring to primary vent

 

[rotw]

Do you refer to double type arrangement dry gas seals ?

 

[rQuestionEngineering]

Yes

 

[rotw]

Double type dry gas seal system arrangement attached according to API 614.
Could you point me out to where the flare is meant to be ?

 

[georgeverghese]

It is tempting to recover primary vent fuel gas, but we often decide not to do this, since minor fluctuations in flare gas recovery compressor suction pressure can mess up the flow of this FG at the dry gas seal, leading to a compressor USD. Essentially, overall facility availability will become a strong function of the reliability of the flare gas recovery compressor and its process controls. In a large facility, there may be many other streams going into flare gas compressor suction, and some of them may cause disturbances to the recovery compressor suction pressure.
Suggest letting it go direct to LP flare - its a small stream, probably smaller flow than the leaking PSVs' and ESD depressuring valves in the facility.

 

[JJPellin]

For a double arrangement, I can't see how this would be practical. For a tandem arrangement, it is possible. We recover the primary seal vent for our tandem seals. We only do this by virtue of the fact that we recover all flare gas. Unless the seal gas was incredibly valuable, I cannot imagine how it could be economically viable to build a recovery system just to recover this tiny stream of gas.

Johnny Pellin