What material should I choose for the instruments and valves used with concentrated sulfuric acid?
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{:3_49:} I’m adding a 98% concentrated sulfuric acid storage tank here; the inlet and outlet pipes for this tank are made of 16MN material. I read online that this material is not resistant to corrosion, while the level gauge manufacturer said that 316L would be sufficient. I still need to buy three manual valves: two for the differential pressure level gauge and one for the shut-off valve. What material is good for these valves? . . Carbon steel? ?
The valve needs to function, so it cannot be determined based on the pipe material. Fluorine-lined lining is recommended
Fluorinated-lined valves are better, as they offer better corrosion resistance
{:3_47:} I plan to buy one with a carbon steel lining coated in fluorine
There is no need for fluorine-coated materials; 98% concentrated sulfuric acid has weak corrosivity, while dilute sulfuric acid is more corrosive, so stainless steel is sufficient.
Use fluorinated-lined valves; they offer good cost-performance
Fluorinated lining offers the best cost-performance ratio; other manufacturers use 904L, 316, and 316L
For concentrated sulfuric acid, carbon steel is suitable; for the rest, you can choose whatever you want. You have money, so do whatever you want. If you give me a red envelope, hire me again – I’ll be your lackey and ready to do whatever you tell me
Industrial concentrated sulfuric acid is not simply a mixture of sulfuric acid and water; therefore, it is recommended to use fluoropolymer-lined valves or fittings. Cast iron options are better than stainless steel ones. You can ask @ValveMingMing on the second floor – his company’s equipment and fittings may be suitable for use
For 98% sulfuric acid, carbon steel does exhibit relatively good corrosion resistance; however, it is only suitable for use as material in storage tanks. At temperatures above 70 degrees Celsius, concentrated sulfuric acid reacts with carbon steel, causing erosion of the valves. Moreover, once concentrated sulfuric acid absorbs water vapor and turns into dilute sulfuric acid, carbon steel will be corroded. Therefore, it is recommended to use fluorinated materials for valves