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Equipment conservation
- Thread starter PI055
- Start date
LittleInch
Petroleum
PI055,
A detailed procedure only you can create.
In general for a pig trap you would want to drain it of any liquid / vent off any gas, then purge at low pressure from one end to the other, then pressure to a nominal pressure - say 5 bar, with dry Nitrogen.
A drain vessel is not as easy. If to be left for a long time then you could remove as much liquid as possible, then you need to get into the tank to get the last dregs out, dry it and then maybe spray the inside with some sort of thin oil or wax?
Or fill it with inhibited water to the top and then pump it all out when you want to use it. Most drain tanks are atmospheric so you can't shut it off and pressurise them.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
A detailed procedure only you can create.
In general for a pig trap you would want to drain it of any liquid / vent off any gas, then purge at low pressure from one end to the other, then pressure to a nominal pressure - say 5 bar, with dry Nitrogen.
A drain vessel is not as easy. If to be left for a long time then you could remove as much liquid as possible, then you need to get into the tank to get the last dregs out, dry it and then maybe spray the inside with some sort of thin oil or wax?
Or fill it with inhibited water to the top and then pump it all out when you want to use it. Most drain tanks are atmospheric so you can't shut it off and pressurise them.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
- Thread starter
- #3
LittleInch thank you for answer. When you speaking about pig trap purging and nitrogen pressurizing, in this case the whole pipeline from pig shall be put out of use and conserved for some time. Does that mean that whole pipeline should be purged and then I isolate receiver and pressurize it with nitrogen ?
LittleInch
Petroleum
That's a different question....
There are lots of variable you need to consider which we don't know.
Such as
What is in the pipeline? Gas, liquid, any water?
Do you need to empty the pipeline?
If so for how long?
How long / big is the pipeline?
So yes nitrogen purging and a hold pressure of a nominal 5 bar will preserve it quite well and allow you to monitor the pipeline for any leaks or damage resulting in a loss of containment. But be sure to mark that the pipeline is under Nitrogen pressure as if someone decides to vent it they can have asphyxiation risks.
Inhibited water is often used as well for liquid lines as it prevents any flotation and is cheap.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
There are lots of variable you need to consider which we don't know.
Such as
What is in the pipeline? Gas, liquid, any water?
Do you need to empty the pipeline?
If so for how long?
How long / big is the pipeline?
So yes nitrogen purging and a hold pressure of a nominal 5 bar will preserve it quite well and allow you to monitor the pipeline for any leaks or damage resulting in a loss of containment. But be sure to mark that the pipeline is under Nitrogen pressure as if someone decides to vent it they can have asphyxiation risks.
Inhibited water is often used as well for liquid lines as it prevents any flotation and is cheap.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Does anyone else have problem mothballing a vessel or pipeline with a positive N2 pressure? Seems to me if the vessel is under pressure it is still an operating pressure vessel and all the local regulations apply for 3rd party inspection, certification etc.
Now if vessel was under a small constant flow of N2 and no way of being pressured (e.g remove drain valves and fit waterfilled loop seals). It is not an operating vessel and the above does not apply.
Now if vessel was under a small constant flow of N2 and no way of being pressured (e.g remove drain valves and fit waterfilled loop seals). It is not an operating vessel and the above does not apply.
- Thread starter
- #6
So is it in service now? If so you'd probably want to flush it with meg water mix or similar to remove hydrocarbons and then leave it filled with treated water (corrosion inhibtor, oxygen scavanger etc) as noted above. You may want a specific cleanliness (i.e. oil in water ppm) which would require sampling during flushing till it reaches desired cleanliness. The PLR's could be purged with nitrogen but depending on the length of pipeline it would be pretty expensive to purge a 36" oil line when you could use inhibited water.
LittleInch
Petroleum
Yes it needs cleaning.
Usually pushed by water and then flushed or a set of pigs to follow the first before finally filling with inhibited water is my best suggestion.
You can clear it and then fill with Nitrogen, but then it still remains "live" as it's under pressure, but it could be quite expensive in terms of the amount of Nitrogen
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Usually pushed by water and then flushed or a set of pigs to follow the first before finally filling with inhibited water is my best suggestion.
You can clear it and then fill with Nitrogen, but then it still remains "live" as it's under pressure, but it could be quite expensive in terms of the amount of Nitrogen
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
- Thread starter
- #9
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