New pipeline construction - corrosion inhibitor
New pipeline construction - corrosion inhibitor
(OP)
Hi all,
Is it recommended to run a batch of corrosion inhibitor (oil-based for instance) after hydrostatically testing a pipeline with a water/methanol mixture in case the pipeline commissioning is delayed or a pipeline drying may be sufficient to get rid of the water/methanol mixture?
Thank you,
Sam
Is it recommended to run a batch of corrosion inhibitor (oil-based for instance) after hydrostatically testing a pipeline with a water/methanol mixture in case the pipeline commissioning is delayed or a pipeline drying may be sufficient to get rid of the water/methanol mixture?
Thank you,
Sam





RE: New pipeline construction - corrosion inhibitor
-pmover
RE: New pipeline construction - corrosion inhibitor
Thanks pmover,
It's a fairly long pipeline & big inch, but the pressure and drying are done on sections of pipe anyway.
I'll reformulate my question: Because of the use of a water/methanol mixture during the pressure test, and as the drying may not allow us to get rid of all water/methanol, would it be better to run a corrosion inhibitor batch - provided of course it's done efficiently - to make sure that no water/methanol remains in the pipeline?
Sam
RE: New pipeline construction - corrosion inhibitor
Most stuff labeled "corrosion inhibitor" (as opposed to "surface treatment" or "paint") is intended to be run along with process fluids and wants to be in a continuous phase liquid. Pigging in a batch of very expensive corrosion inhibitor strikes me as a good way to spend a bunch of money and develop a difficult disposal problem without adding any value at all.
I can live with (and even sometimes recommend) corrosion inhibitor in lines designed to be liquid-full in normal operations. I strongly resist ever adding it to a line that is intended to be gas full because the transport of the chemicals is so hit-and-miss (mostly miss) that they accumulate in early low points and never get to the later ones.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: New pipeline construction - corrosion inhibitor
How would you ideally deal with this situation knowing that the pipeline commissioning will take place from one to two years after the construction is completed?
Sam
RE: New pipeline construction - corrosion inhibitor
Emptying it, running a series of drying pigs, batchiing corrosion inhibitor, shut in full of air for a couple of years sounds to me like a recipe from MacBeth to mix up a cauldron of serious trouble. If I found a pipe in that condition I'd run another pig with nitrogen and leave the system with 3-5 psig of nitrogen pressure. Just make damn sure that the nitrogen-fill process includes prohibitions against injecting it below 60F (the gas not the pipe or ambient). Bulk nitrogen is really really cold and if the truck driver isn't told to keep the temp up then he'll tend to pump as fast as he can. There have been a couple of recent fatalities from the brittle failure that resulted, in neither case had the design engineer specified the injection temperature.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: New pipeline construction - corrosion inhibitor
One more question though. What would you fire the PM?
Sam
RE: New pipeline construction - corrosion inhibitor
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: New pipeline construction - corrosion inhibitor
"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek
RE: New pipeline construction - corrosion inhibitor
RE: New pipeline construction - corrosion inhibitor
RE: New pipeline construction - corrosion inhibitor
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.