Material for Chiiled Water System

[Xeros]

hi,

I'm Xeros.

I have a Chilled Water System.

Chilled Water is Demineralized Water and Ethylene Glycol (20% Glycol solution).

Operating temperature is -15 degree C.

I know that Demineralized water is very corrosive to Carbon steel. Generally We use Stainless steel.

However,
If Glycol for anti freezing is added, is this Chilled Water (20% glycol solution=demineriazed water + glycol)corrosive to carbon steel?

If not corrosive to carbon steel, I'm happy.

If corrosive to carbon steel, What is the method for preventing corrosion to carbon steel.

I heard that Sodium nitrite treatment (about 500 - 700 ppm)could be applied for preventing corrosin.

Do anyone have a reference for nitrite treatment?
please, inform me...

Or,

Are there different kind of method for preventing corrosion?


Best regards,

 

[btrueblood]

Xeros,

You may want to post this question in the corrosion engineering forum instead. In general, there is nothing about ethylene glycol and water solutions that prevents corrosion of carbon steel; commercial glycol anti-freeze solutions include corrosion inhibitors. Your system needs similar inhibitors added to reduce corrosion. Yes, nitrite can reduce oxidation in closed systems, but it's also a pretty toxic chemical. Suggest you google corrosion inhibitors, or post to the suggested forum to find suppliers for corrosion inhibitor chemicals. Also, why ethylene glycol, why not propylene glycol (the latter is much safer/non-toxic and gives very similar freeze protection).

 

[deanc]

http://www.infratrans.gov.ab.ca/INFTRA_Content/docType306/Production/TechPres28.pdf

http://www.google.com/search?hl=en&q=converting+a+closed+loop+system+to+glycol&btnG=Google+Search

Have a look.