Acid Dew Point Corrosion - H2SO4
Acid Dew Point Corrosion - H2SO4
(OP)
Any suggestions on a benchtop recipe to mimic the acid concentration encountered in an oil-fired boiler's exhaust ductwork? We are upgrading materials and would like to run some immersion tests to see if there is a galvanic effect of the weld filler and DMW when we tie the new to the old material.
Don't tell me to eliminate the entire dissimilar metal weld - we were lucky enough to get the $ for a partial upgrade.
Don't tell me to eliminate the entire dissimilar metal weld - we were lucky enough to get the $ for a partial upgrade.





RE: Acid Dew Point Corrosion - H2SO4
I don't think an immersion test will be of any practical use because the pH of acid dew point corrosion is influenced by many variables in exhaust gas ducts at power plants. I have seen the pH range from 4 down to 1. The immersion test results using dilute sulfuric acid will not be meaningful, and will skew your data.
The most important point is that you have located the weld transition in the hot zone (safely above the dew point temperature) of the duct. This would reduce any changes of acid dew point corrosion and prevent any moisture formation at the DMW - (e.g., no moisture, no galvanic attack).
RE: Acid Dew Point Corrosion - H2SO4
RE: Acid Dew Point Corrosion - H2SO4
Regarding the DMW, corrosion will occur if you have deposits that can absorb moisture.
If you want to evaluate corrosion affects, I would weld some DMW coupons that you can handle and obtain some of the ash from the duct. Generously spread the ash deposits over the entire coupon and use a spray mist to provide moisture. Monitor over time and see what happens on the surface of the coupons.
RE: Acid Dew Point Corrosion - H2SO4
you should have such tests installed in your duct work. Few bench top testing arrangements will provide a realistic measure of what is going on.
RE: Acid Dew Point Corrosion - H2SO4
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Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: Acid Dew Point Corrosion - H2SO4