Selective Corrosion of 2205 Duplex SS
Selective Corrosion of 2205 Duplex SS
(OP)
I am investigating some badly corroded 1" HX tubes from a biodiesel production facility. The inputs include fatty acids, methanol, secret sauce, and a fraction of 1% sulfuric acid. Sludge deposits were found, but the corrosion was 360°, with some preferential corrosion at the weld. I have not yet examined the tubes up close, so this is all the information I have.
Is there anything listed (or not listed) here that could cause aggressive corrosion?
Is there anything listed (or not listed) here that could cause aggressive corrosion?





RE: Selective Corrosion of 2205 Duplex SS
2. What is the minimum pH in the system?
3. What is the maximum temperature?
4. What is the Cl content?
5. Which fatty acids?
6. What about other metal ions, Fe?
Mixed acids with any chlorides present are not good.
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Plymouth Tube
RE: Selective Corrosion of 2205 Duplex SS
RE: Selective Corrosion of 2205 Duplex SS
RE: Selective Corrosion of 2205 Duplex SS
Temp, pH, and chlorides are what you need to know.
My guess is that pH and chlorides are unknown/uncontrolled.
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Plymouth Tube
RE: Selective Corrosion of 2205 Duplex SS
RE: Selective Corrosion of 2205 Duplex SS
The question now is which way to turn. This industry (biodiesel production from renderings) is still fairly young, are there any established alloys so far? I am thinking we will end up with a superaustenitic of some variety.
Any thoughts/suggestions?