Glycol corrosion

[MaxNeg63]

I've been asked to verify if a carbon steel pipe filled with a mixture of ethylen glycol and distilled water (ratio 1,5/1)at ambient temperature and with no flow can corrode: filling was done in may this year and expected un-filling shall be in next December. In my opinion answer is no since glycol decomposes only at relatively high temperatures but on the other hand the use of glycol+water mixture without any corrosion inhibitor is not usual

 

[EdStainless]

Will there be some superifcial corrosion and rust in the system, yes. The solution is conductive and there are bound to be some differences in surface conditions or oxogen levels that result in some light general corrosion.
Sounds like equipment put into wet lay-up. An inhibitor would have been cheap insurance.

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Corrosion, every where, all the time.
Manage it or it will manage you.

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[MaxNeg63]

Therefore my understyanding is: useless to inject something now, better to require a complete pigging of the line once it's been unfilled. Correct?

 

[EdStainless]

It may be too late now. Better to just plan on cleaning after you drain it.
Anyone else have any thoughts? I don't think leaving it as is will cause any great problems.
If you do inject some inhibitor now you can minimize your cleaning work later.

= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[CESSNA1]

MAXNEG63: Pure ethylene glycol will not hack it. Automotive antifreezes made from E.G. have a corrosion inhibitor added. If you are using an automotive type E.G. solution it should have the corrosion inhibitor. If it is pure E.G. it most likely will not. That is why after years of neglect, automotive cooling systems rust up. The anti-corrosion agents are used up and the cast iron is no longer protected.

Regards
Dave