Corrosion probe and corrosion coupon
Corrosion probe and corrosion coupon
(OP)
What is the difference between corrosion coupon and corrosion probe ?
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Corrosion probe and corrosion coupon
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RE: Corrosion probe and corrosion coupon
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Corrosion probe and corrosion coupon
If it ain't broke, don't fix it. If it's not safe ... make it that way.
RE: Corrosion probe and corrosion coupon
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: Corrosion probe and corrosion coupon
If it ain't broke, don't fix it. If it's not safe ... make it that way.
RE: Corrosion probe and corrosion coupon
Same with corrosion chemicals in gas lines--they accumulate at the first sag because the gas can't move them farther and the chemicals never get to where the corrosion cells are, but we keep pumping that crap into gas lines to the tune of a few billion dollars/year. The attitude that "doing something probably ineffective is better than doing nothing" is pretty pervasive. I've cut open lines at sags that were pure (toxic or poisonous) chemicals and I have to disagree with the idea that injecting chemicals in gas lines is better than doing nothing. It is actually far worse than worthless.
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: Corrosion probe and corrosion coupon
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Corrosion probe and corrosion coupon
I've kept track of the corrosion failures I've been asked to investigate over the years and over 80% of the failures have been on "protected" lines (some combination of cathodic and/or chemical injection) that were not pigged. "Protected" lines make up about 30% of the lines I see in my practice, but they make up the lion's share of the failures. I have never seen a single failure on a line that was pigged regularly (and adding corrosion chemicals to the pig run just costs money without providing any real benefit since pigged lines don't rot).
As an aside; at a conference a decade ago I had occasion to ask the Chief Metallurgist of a major Oil & Gas chemical supplier to join me for a drink. After far too many drinks I asked him what was the transport mechanism for biocides in a low pressure gas line. He was just drunk enough to say "quarterly profit and loss statements". In vino veritas.
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: Corrosion probe and corrosion coupon
If it ain't broke, don't fix it. If it's not safe ... make it that way.
RE: Corrosion probe and corrosion coupon
RE: Corrosion probe and corrosion coupon
I don't know how the question became a discussion on chemical inhibition, but David I have certainly seen my share of corrosion failures on lines that were pigged regularly (twice per month) with no chemical inhibition. I can also say if I stopped applying chemical to most of the sour multiphase pipelines I manage I would see a spike in the number of failures, as this was the case before applying the inhibitor with everything else equal. Like anything else though, you have to know the details of what you are doing rather than just put chemicals in the line and hope for the best.
RE: Corrosion probe and corrosion coupon
I would love to know the details on that. I've consulted on some pretty sour wet gas lines that were regularly pigged and when we've cut them open for tie-ins, the pipe looked fine every time. Some of the non-piggable laterals were a very different story, but in the absence of standing water there just isn't any place for the gas to facilitate the creation of a corrosive cell (either acid attack or MIC). It seems like twice monthly pigging would be adequate to disturb the liquid pools before they become a problem (I often have to pig more often than that for pressure-drop reasons, but not for corrosion).
I'm not saying you haven't seen what you've seen, it is just so counter to my experience that I would really like to know more.
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: Corrosion probe and corrosion coupon
The Canadians have the best experience with sour gas corrosion control
http://www.capp.ca/getdoc.aspx?DocId=155644&DT...
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04