Corrosion in Galvanized Piping with glycol
Corrosion in Galvanized Piping with glycol
(OP)
Hello All,
One of our compressors that is going offshore has galvanized piping for the coolant lines(compressor manufacturers called it "hoses are carbon steel which are zinc plated with a clear passivate.")
They have stated that they have used monopropylene glycol and Ethylene glycol (ethanediol) without any problems.
Our operational temperatures is hot and humid (generally 40C at 90-100% humidity)
My question is, is it safe to use this type of glycol-water mix (generally thinking 50-50)? I have heard and read that the glycol reacts with the Zinc in the threads and pipe and cause corrosion.
If not, maybe water with corrosion inhibitor would be safe? (since the lowest temps we might see is 16C)
Thanks for the space!
One of our compressors that is going offshore has galvanized piping for the coolant lines(compressor manufacturers called it "hoses are carbon steel which are zinc plated with a clear passivate.")
They have stated that they have used monopropylene glycol and Ethylene glycol (ethanediol) without any problems.
Our operational temperatures is hot and humid (generally 40C at 90-100% humidity)
My question is, is it safe to use this type of glycol-water mix (generally thinking 50-50)? I have heard and read that the glycol reacts with the Zinc in the threads and pipe and cause corrosion.
If not, maybe water with corrosion inhibitor would be safe? (since the lowest temps we might see is 16C)
Thanks for the space!





RE: Corrosion in Galvanized Piping with glycol
"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein
RE: Corrosion in Galvanized Piping with glycol
http://www.evanscooling.com/maintenance/
RE: Corrosion in Galvanized Piping with glycol
RE: Corrosion in Galvanized Piping with glycol
It is a closed loop system, and as metalguy suggested to use the following:
1. TSP - raises the PH level
2. Sodium sulfite to scavenge oxygen
3. biocide to kill any SRBs
Question is I am not familiar with TSP (Trisodium Phosphate?) - unfortunately my area is mostly mechanical. What would raising the PH do in terms of corrosion?
I found information on the other 2. Is there a on-the-shelf chemical that I can purchase and supply and add to water that contains these?
If I am not concerned with biocide, would be great to get the sulfite/TSP in one additive.
Thanks again!
RE: Corrosion in Galvanized Piping with glycol
RE: Corrosion in Galvanized Piping with glycol
If your system doesn't require a lot of coolant, consider using demin. water. You'd then need very little TSP to raise the pH.
Using treated water instead of a glycol mix allows better heat transfer, if that's a concern.
"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein
RE: Corrosion in Galvanized Piping with glycol
http://w
You can also contact the Galvanizeit.org and ask for more data:
"If you would like assistance in determining the reactivity of zinc when exposed to a particular chemical, or if you are interested in a chemical that is not listed in these charts, please contact us online, or call our toll-free technical support at 1.800.468.7732."
h
hope this help
S.
Corrosion Control
RE: Corrosion in Galvanized Piping with glycol
I am going to spec out a pre-mixed additive and just add it to water. I am not sure what kind of water they have available on the off shore rig, but I am positive they have potable water.
I was reading on some good closed loop corrosion inhibitors and came across this:
http://www.amsolv.com/coo-clos.htm
Was looking at this and see some additives I MIGHT be able to use. I'm waiting for the compressor manufacturer to get some input on this. If you guys have any thoughts that would be great.