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?
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:
shows the compositions:
3000-Aluminum + Manganese (up to 1%)
5000-Aluminum + Manganese (up to 5%)
3000-Aluminum + Manganese + Silicon (up to 1% of each)
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)
If you have chlorides present, methanol will cause rapid corrosion of aluminum; aluminum methylene chloride. Formic acid corrosion (from methanol) is also a problem.