Selection of pipeline materials for hydrochloric acid and hydrofluoric acid mixed acid
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The components are hydrochloric acid and hydrofluoric acid, with no other impurities; the temperature is around 50-80 degrees, and the pressure is about 12 kilograms. Can 316L be used?
316L is too expensive; fiberglass will do
You mean the issues of high temperature, pressure, and corrosion resistance, right? The strength is not a problem
It is recommended to choose the F4-lined option (molding process)
Yes, the pressure resistance of fiberglass-reinforced plastic at around 80 degrees is only 4-5 kilograms; at room temperature and for DN…
It must be lined with steel and PTFE; the corrosion is too severe
With such a strong mixed acid and chloride ions present, using 316 is not appropriate. Use the fluorinated lining one
Chloride corrosion is highly dependent on concentration; this factor must be taken into account. 316L steel is fairly resistant to alkalis but not to chlorides; plastic lining can be used as a solution. I was dealing with a similar issue some time ago – 316L storage tanks were to be filled with 4% hydrochloric acid, and subsequently an epoxy resin coating system was applied as anti-corrosion protection
I also feel that 316L cannot be used. The reason is that the pipes were replaced previously; I’m not sure why 316L was chosen back then. Now I want to use another material. Since it’s a flange-connected system, I’m worried about insufficient space, and it would be troublesome to move the equipment