Can 316L be used with 80-degree concentrated sulfuric acid at 99.8% concentration?
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I am currently facing a situation where 99.8% concentrated sulfuric acid is used as the solvent, the operating temperature is 80 degrees Celsius, while the design temperature is 100 degrees Celsius. The operating pressures are approximately -0.1 MPa and 1 MPa respectively. Can 316L material be used under these conditions? What is the annual corrosion rate?
You can do a hanging slice test; it’s not complicated.
Thank you to the person in floor 2. The problem is that there are no conditions for conducting tests at the moment, so I can only turn to other users for help.
One cannot consider only the corrosion caused by concentrated acids; it is also necessary to check whether there are any impurities in the solvent that could affect corrosion. It would be best to conduct a coupon test, which can be done for a few thousand yuan.
For such operating conditions, Monsanto’s ZeCer alloy can be used, as well as XD alloy from Zhejiang Xuanda Group. The materials used in low-temperature recovery systems require even higher standards, but there is no problem with these alloys.
There shouldn’t be any problem, right!!!
It’s better to consult professional engineers; safety comes first! ! !
Sulfuric acid will produce ferric sulfate; does this affect its use as a solvent? The corrosion rate of sulfuric acid on stainless steel includes not only the static corrosion rate but also the dynamic corrosion rate. The dynamics are also related to the acid flow rate. If there is a laboratory, there is an electronic balance, allowing for static tests to be conducted; the cost involved is negligible. Dynamic testing is more complex.
Thank you to everyone above; it is precisely because of the safety and reliability that I am seeking advice from you all. In fact, this is an intermediate container; sulfuric acid, acting as a solvent, needs to flow. Basically, the process pipelines are lined with PTFE, but due to the many rotating components inside the equipment, using PTFE lining is not feasible; therefore, 316L is chosen. In this process, it is best to avoid ferric sulfate, but the impact of ferric sulfate on the main material is not yet clear.
At your concentration and temperature, it’s actually not necessary for PTFE to completely isolate the metal from sulfuric acid; in other words, the PTFE layer can be applied to the metal surface in a way that provides as much coverage as possible, and this will certainly help to reduce the formation of ferric sulfate.