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The shell on our 40 year old water heater at the plant went from pitted to paper thin in about 16 months
I do shutdown work at a paper mill outside Green Bay and we pulled the same heater shell for the third time in five years. Back in 2023 the pitting was maybe a quarter inch deep, mostly surface stuff. When we cut it out in April the wall had dropped from .375 to under .090 in spots near the bottom head. We ran the same water treatment the whole time, so the only real change was they bumped the operating temp up about 40 degrees to keep up with production. Anyone here seen temp creep eat a shell that fast, and did you fix it with a liner, different alloy, or just pull the plug on the setpoint?
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sarah8184d ago
Temp is the killer here, not your water chem. Every 18 to 20 degree bump roughly doubles the corrosion rate on carbon steel, so 40 degrees is like running that shell at four times the speed. We saw the same thing on a deaerator up in Wisconsin Rapids, wall went from .30 to .10 in two heating seasons once they pushed the setpoint. First thing I'd do is check the bottom head area for caustic gouging too, because that temp rise plus your treatment can concentrate stuff down there. A liner buys you time but you're just hiding the problem unless you drop the temp back down. If production won't give up the setpoint, go to a 316L or duplex head and watch your dissolved oxygen like a hawk.
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