Carbon Steel Corrosion from Produced Water
Carbon Steel Corrosion from Produced Water
(OP)
Hi all,
I'm replacing an old section of produced water pipe and am trying to figure out if I should internally coat the carbon steel (A106-B). I don't have any info an the existing pipe so can't use that as a benchmark, however I have a water analysis that shows a chloride content of 13,896 mg/L. The system is closed so there is no oxygen ingress, does anyone have any insight as to what kind of corrosion to expect in this line? Is there a good argument for not internally coating the pipe based on the analysis and fact that there's no oxygen ingress? The new pipe will have a corrosion allowance of 1.5 mm and I've attached the water analysis. Any help would be appreciated. Thanks,
James
I'm replacing an old section of produced water pipe and am trying to figure out if I should internally coat the carbon steel (A106-B). I don't have any info an the existing pipe so can't use that as a benchmark, however I have a water analysis that shows a chloride content of 13,896 mg/L. The system is closed so there is no oxygen ingress, does anyone have any insight as to what kind of corrosion to expect in this line? Is there a good argument for not internally coating the pipe based on the analysis and fact that there's no oxygen ingress? The new pipe will have a corrosion allowance of 1.5 mm and I've attached the water analysis. Any help would be appreciated. Thanks,
James





RE: Carbon Steel Corrosion from Produced Water
what is the service temperature?
did you investigate Langelier Index ? (https://corrosion-doctors.org/Cooling-Water-Towers...)
remark : i think you can say that chloride content is 14000ppm or 1.4% because 13,896 is too precise and stings the eyes.
regards
RE: Carbon Steel Corrosion from Produced Water
RE: Carbon Steel Corrosion from Produced Water
RE: Carbon Steel Corrosion from Produced Water
Another test would be the use of a field dissolved oxygen meter capable of reading at least somewhat below 0.5-1.0 mg/L of water as O2.
If oxygen is confirmed or presumptively confirmed low, then by all means proceed.
Any possibility of air ingress by some Venturi effect on the line at any point, and downstream from that point you will be asking for trouble.
RE: Carbon Steel Corrosion from Produced Water
Why do you think you need coating?
Stiff polygon says corrosive. Langelier or Ryznar index maybe says pitting corrosion, but you need operation temperature.
What about the flow: continous or intermitent?
Do you clea perodically the infernal surface of the pipe?
RE: Carbon Steel Corrosion from Produced Water
0.5 to 1 mg/L is roughly 0.5 to 1 ppm !! this is quite high for oxygen in water vs. corrosion.
low oxygen is << 50-100 ppb and oxygen probes could usually measure down to few ppb. when deaerated water is required, less than 10ppb oxygen can be usually be met.
RE: Carbon Steel Corrosion from Produced Water
it does not meet the definition of de-oxygenated water. With the chemistry of the original poster's water, there had better not be much oxygen, or there will be problems.
Some instruments are better (lower limits of detectability) than others. Having said that, the quenched luminescence probes are relatively easily calibrated when they
are set up for readings in the ppb range in the first place, although some of those meters are meant for tests on wastewater, where they consistently look at some fraction of saturation above 80%.
For boiler applications, I am well aware of the requirements for exceedingly low oxygen residuals, unless it is oxygenated treatment protocol, where it is around 30 ppb, fully de-aerated, then back injected when intentional.
RE: Carbon Steel Corrosion from Produced Water
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Carbon Steel Corrosion from Produced Water
RE: Carbon Steel Corrosion from Produced Water
based on the analysis this is wastewater not produced water (could be e.g. brine from softener regeneration, reverse osmosis concentrate, etc.). The water has 200 German degrees of hardness!
Given the huge salinity, low pH (note 7,3 IS corrosive for carbon steel) I would suggest using coating or plastic pipe if possible.
RE: Carbon Steel Corrosion from Produced Water
I cannot agree more, this is quite corrosive water in its nature, and with this much hardness, trouble is likely.
RE: Carbon Steel Corrosion from Produced Water