Methanol and aluminum

[IFRs]

I am aware that Methanol in certain concentrations will corrode aluminum. What I was not aware of is that aluminum alloy 3003 is preferentially corroded as compared to alloys 6061, 6063 and 5052. Can someone explain why?

Thanks!!

 

[IFRs]

Just wonderng if anyone has any thoughts on this issue?

 

[mizkn]

Giving more details (type of corrosion you see and location(s), vessel located outside? is it insulated? near coast of salt air?, temp & press of process, vessel, exchanger, fin tubes, etc) would assist a reply here...

If your aluminum is in contact with SS then you have galvanic corrosion occuring. i do not have a specific experience base to address this but the web has an abundance of information:

For example,

http://www.saf-airliquide.com/chapter03/en/alusite/apport2.htm

shows the compositions:
3000-Aluminum + Manganese (up to 1%)
5000-Aluminum + Manganese (up to 5%)
3000-Aluminum + Manganese + Silicon (up to 1% of each)

Or coated aluminum and corrosion photos:

http://www2.umist.ac.uk/corrosion/JCSE/Volume2/Paper36/v2p36.html

http://www.orioninstruments.com/html/coorsion_resistance.asp

I placed Methanol, Aluminum 3003, and "A" corrosion rate of <0.05mm/year is good for 90F (the sun alone could heat it hight than that depending on your environment)

good luck.

 

[AEF]

If you have chlorides present, methanol will cause rapid corrosion of aluminum; aluminum methylene chloride. Formic acid corrosion (from methanol) is also a problem.

 

[IFRs]

AEF - thanks for the info. How does the alloying elements affect the corrosion rate?