sea water corrosion and fouling protection

[aligali]

hi dear friends
What is the best water treatment methode for protection of fouling formation and corrosion in sea water coolant system of an ship?

 

[strider6]

10th International Congress on Marine Corrosion
and Fouling,University of Melbourne, February 1999

http://www.dsto.defence.gov.au/publications/2396/DSTO-GD-0287.pdf

To prevent bio-fouling in seawater systems
– Chlorination by chlorine gas or hypo chlorite, typically up to 0.5
ppm residual chlorine (Cl2 + HOCl + OCl-)
– Combined Cu and chlorine, typically 5 ppb Cu and 0.1 ppm residual chlorine

http://www.efcweb.org/efcweb_media/Downloads/Attachment+8-p-218.pdf

Electrochlorination System Technology

http://www.farwst.com/fwst/marine/electrochlorination2.htm

S

Corrosion Prevention & Corrosion Control

 

[EdStainless]

In addition there are systems in use that rely on generating either Cu or Al ions in the cooling water. Both of these metals act as biocydes.

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[mshimko]

Assuming this is a flow-through system, the best way to control corrosion is matarial selection.

The best way to control fouling is material selection plus an injection of a biocide or film-forming material.
Be aware, though, the environmentalists out there tend to oppose both.

Some organizations are tring to ban copper-rich piping (copper-nickel), while at the same time are trying to ban chlorination and other biocides.

I'm familier with several systems that generate copper, however they don't produce enough coppere to do anything when the pumps are on, and the onl;y benefit is when the pumps are off. This could be a viable process, except environmental restrictions (current and/or future) on "slugs" of copper rich discharges when you turn the pumps on.

 

[EdStainless]

I have seen ships running Cu or Al ion systems continuously. It isn't enough at high flow, but with the high flows fouling is minimal.

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