closed airtight container and corrosion
closed airtight container and corrosion
(OP)
Hello,
I would think the corrosion rate is very low in a closed airtight galvanized steel container containing liquid mix (40% water and 60% antifreeze (Ethylene Glycol)). The container can have 50% air and 50% the liquid mix or so. The tank size is about one meter cube and this needs to be placed outdoor in cold and warm weather. I would think the corrosion rate will slow down extremely once the oxygen in the close contained is completely used. But I am not sure and feels the antifreeze may affect the corrosion rate. We are thinking the galvanized container to last about 50 years or so. Will someone who knows better on corrosion control can comment and add their opinion on this please? Thank you.
I would think the corrosion rate is very low in a closed airtight galvanized steel container containing liquid mix (40% water and 60% antifreeze (Ethylene Glycol)). The container can have 50% air and 50% the liquid mix or so. The tank size is about one meter cube and this needs to be placed outdoor in cold and warm weather. I would think the corrosion rate will slow down extremely once the oxygen in the close contained is completely used. But I am not sure and feels the antifreeze may affect the corrosion rate. We are thinking the galvanized container to last about 50 years or so. Will someone who knows better on corrosion control can comment and add their opinion on this please? Thank you.
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RE: closed airtight container and corrosion
One problem is that the inhibitors work best on the submerged metal so you may want to consider a small expansion tank above the unit fabricated from corrosion resistant materials.
You shouldn't need to galvanize the tank.
RE: closed airtight container and corrosion
Two small questions:
1. What will be the mix ratio of carboxylic acid and water in general? in PPM ?
2. Does antifreeze will have any role in accelerating corrosion in the closed container ?
Thanks
RE: closed airtight container and corrosion
For the older generation of treatment, 3000 ppm sodium nitrite was the norm for an initial dose.
The newer carboxylate based systems generally go off specific gravity so I don't know a concentration off the top of my head.
These are commercially available options.
https://www.chevronlubricants.com/en_us/home/produ...
RE: closed airtight container and corrosion
Steve Jones
Corrosion Management Consultant
www.linkedin.com/in/drstevejones
All answers are personal opinions only and are in no way connected with any employer.
RE: closed airtight container and corrosion
Are there any other metals in that loop?
You need consider everything that the fluid touches.
And even though the sheet steel is galvanized what about your welds?
Will you post-weld galv?
If the welds will be left bare then all of the steel should be bare.
If only the welds are bare then you risk that any corrosion will be concentrated there.
What about venting, the air will heat and expand in the days so will there be a pressure relief.
And then when cooling at nights it will want to suck in more fresh air.
The biggest risk is in the headspace, especially just above the fluid level.
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P.E. Metallurgy, consulting work welcomed
RE: closed airtight container and corrosion
So is there a loop that this fluid circulates through? No the same fluid will be there all the time.
Are there any other metals in that loop? No
You need consider everything that the fluid touches.
And even though the sheet steel is galvanized what about your welds?
Will you post-weld galv? Galvanization is the last step in fabrication so the welds are also galvanized.
If the welds will be left bare then all of the steel should be bare.
If only the welds are bare then you risk that any corrosion will be concentrated there.
What about venting, the air will heat and expand in the days so will there be a pressure relief. its airtight container and so no venting.
And then when cooling at nights it will want to suck in more fresh air. airtight container.
The biggest risk is in the headspace, especially just above the fluid level. why ?
RE: closed airtight container and corrosion
Add to that, evaporation in the head space concentrates corrosive substances.
Thirdly, any galvanic protection is ineffective in the headspace.
RE: closed airtight container and corrosion
what is this thing? Will the level rise and fall within the chamber - sounds like an expansion tank to me -
What sort of inspection can you do on it?
How often will the fluid be changed?
Can't you make it out of plastic? or GRE or something that doesn't corrode like Duplex. If it's going to last 50 years then it needs to be bullet proof. Galvanised steel isn't that.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: closed airtight container and corrosion
And how will it be sealed? A pipe plug would not be good enough to prevent breathing.
Find someone that will blow a plastic liner into your steel box.
And then allow it to breath.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
RE: closed airtight container and corrosion
RE: closed airtight container and corrosion
RE: closed airtight container and corrosion
Its just a liquid container which is not allowed to freeze and can be use in vibration control of structure.
RE: closed airtight container and corrosion