Seeking help with the issue of corrosion margin for pressure vessels
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I am designing a jacketed vessel; the inner tube is made of stainless steel 321, while the jacket is made of Q245R. The inner tube contains a lithium carbonate solution. I would like to ask experts what corrosion margin should be chosen. The design parameters are provided in the attachment. Also, I would like to know how the corrosion margin is generally determined
Please refer to the \"Corrosion Data and Material Selection Manual\" (edited by Zuo Jingyi and Zuo Yu) or information provided by the user...
We usually also consult corrosion manuals, but the range values provided in those manuals can sometimes be too broad; it is advisable to take into account actual user experience along with the information in the manuals
We usually also consult corrosion manuals, but the range values provided in those manuals can sometimes be too broad; it is advisable to take into account actual user experience along with the information in the manuals
Refer to the \"Corrosion Data and Material Selection Manual\" (edited by Zuo Jingyi and Zuo Yu); lithium hydroxide exhibits good corrosion resistance in S32168, with a corrosion rate of 0.05–0.1 mm/year. Based on the design life, grade C2 can be selected, and a thickness of 2 mm is sufficient for the jacket (over a period of 15 years). However, the most accurate information should come from the property owners, as only they know the specific details.
The determination of corrosion margin isn’t actually that strict. For this equipment, a corrosion margin of 0 can be adopted for the inner cylinder. The medium inside the jacket is usually cooling water, cooled brine, water vapor, ethylene glycol, etc., for which a margin of 2 mm can be used.
Excuse me, expert: the inner cylinder contains lithium hydroxide, which is a corrosive medium – why is a corrosion margin of 0 chosen? The jacket contains ethylene glycol, which should not be very corrosive; then why is a margin of 2 chosen?
I have specified a corrosion margin of 1 mm for the inner tube jacket during the design – I’m not sure if that’s sufficient, with a design life of 20 years