High pressure drop control via self regulated PCV

[KSO1]

Hello All,

We have wellhead gas with min/max pressure ranging from 113 to 245 bar at flow range from 0.6 to 5 MMSCFD. For some wells this gas will go to flare and for others, the gas will go to multiphase manifold piping.

The PCV needed is downstream of Simplex orifice plate needed for metering. The pipe size out of the well is 2" in diameter but increases to 6" prior to Simplex orifice plate.

The objective is to control upstream pressure at setpoint of 203 bar and downstream pressure at 50 bar(setpoint can be between 15 to 50 bar). ESD will open if upstream pressure exceeds 245 bar.

How can we control upstream pressure at setpoint of 203 bar and also control downstream pressure at a setpoint between 15 and 50 bar(i.e, we can set at 15, 30,..or upto 50 bar)?

Sense initial pressue is high, PCV class will be 2500; we can reduce pipe size to 3". Can this be done? If pressure drop is too high(i.e., 203 to 50 bar) due to possible freezing, please advise of possible solution. Please explain if multiple control valves setup in series will work and list of companies/valves that will work to resolve this issue.

Thanks,
KSO

 

[BigInch]

ESD closes on high pressure to shut in the well stream, right?

100 barg cut is possible, 200+ barg cut is pretty high.
Especially with well streams, containing foreign particles, sand, etc. Fischer at

http://www.emersonprocess.com/fisher/

might have a solution. Suggest you talk to them about it.

The best way to control this stream is a pressure control valve controlling its downstream pressure to 50 barg and letting upstream pressure float between normal and ESD cutoff pressure. Its 200+ Barg to 50 is a big cut, but it is possible. It might become a matter of how many times you can afford to maintain it. An orifice, with this valve downstream, may help, as the orifice could possibly take a lot of the pressure cut, and still let this valve have a reasonable degree of flow and pressure control functionality.

Control the 50 barg manifold in the same manner with a control valve between the manifold and downstream lines or at the end of the downstream pipeline, as that enters into some other pipeline or process. 50 Barg to below, doesn't sound like much of a problem. But then again, even that can depend on the cleanliness of your well streams.

http://virtualpipeline.spaces.msn.com

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