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Process design

Process design

(OP)
Dear all , Good day

I would like to ask about some issues & if it could be solved.

We here in gas plant consist of three trains SRU & SWEET GAS. We suffering when one of trains or the three trains went shut down, we have to burn all the gases coming from the platform which about 120 km from our plant, in order empty all the line from the platform to the our plant.

The burnt amount is too high & effect the zone around the plant " envori. impact". what i am thinking, is it possible to add pressures vessel could hold all the amount of gas in side the line instead of burnet.

RE: Process design

Why do you need to empty the pipeline because your plant (or a train within the plant) shuts down?

But your question is not that difficult to answer: The volume in your pipeline can easily be calculated, and the pressure vessel shall be large enough at the pressure your are contemplating (hint either the pressure will be extremely high or the vessel very large or both)

Best regards, Morten

RE: Process design

Yes, why do you have to empty the entire pipeline? Can you not operate the platform to produce less gas?

RE: Process design

I'm suspecting possible Hydrate formation issues if the pipeline is kept pressurized for longer periods after the onshore plant is shut down.

If this is the case, you better investigate what causes the plant/trains to trip and whether there is any way this can be mitigated - maybe to revise interlocks, check the set points, increase reliability/integrity of safety loops, revise operating scenarios etc. We don't know anything about the system you operate so we can't reply with more details.

Dejan IVANOVIC
Process Engineer, MSChE

RE: Process design

(OP)
Dears thanks for your replies,

We have to blow down the gas to the plant flaers. Thai is the company rule.

what i mean it is not possible here as stated in country regulation to burn the gas more the 10 hours in order to avoid the emission to the area.

Now it takes more then 12 hours to burnt all the gases in the line. Even if the platform stopped you still need empty the gas until the pressure in the line minimized

RE: Process design

(OP)

What i mean here if the plant totally shut down

RE: Process design

OK, but the answer is the same: Yes you can build a vessel, and yes its not difficult to estimate the design knowing you operating parameters. You would get a smaller vessel with a compressor, or would have to settle with only storing a given fraction of your gas if you didnt have one since final pressure will be identical for the pipeline and vessel if you dont have a compressor.

To me it seems like a dead end - unless you have an abandoned well suited for re-injection/back production near your plant (or at the upstream end in fact). Again here you would need a compresor for injectiong. Its sems like a much easier taks to challenge these "company rules"

RE: Process design

There are hydrate issues with a pipeline at no flow as the pipeline cools down ? You could avoid this blowdown if the production gas (at the source end) is doped with ethylene glycol or some other hydrate inhibitor ?

Hydrate inhibitor wont be practical if you have large volumes of production water to deal with.

RE: Process design

It is very hard to troubleshoot a problem that has unknown cause(s). There is indefinite number of potential solutions.

Dejan IVANOVIC
Process Engineer, MSChE

RE: Process design

120 km of line? The line is at temperature equilibrium in 10 km, so hydrates at a stopped flow is not the issue?


Etop is correct, what is the issue?

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