What kind of gasket is generally suitable for sulfuric acid pipelines?
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What kind of gasket is generally suitable for sulfuric acid pipelines? The chief engineer said to avoid using PTFE gaskets as much as possible, as they are too hard and prone to leakage I’d like to hear everyone’s opinions.
No way, these gaskets are the most widely used
Our unit uses PTFE gaskets, and there are no problems. What is the material of your pipes?
What your chief engineer said makes sense; acid-resistant rubber can be used
I use PTFE gaskets here, but acid-resistant rubber gaskets would be better. But the pressure issue needs to be taken into account
Nitrile is the most common; PVC is also used, but tetrafluoroethylene is preferred, or a composite of tetrafluoroethylene and nitrile
I use PVC gaskets on my end as well.
For what concentration? We use ordinary metal graphite wound gaskets for 20% fuming sulfuric acid, while 316L gaskets are used for 98% acid
It also depends on the temperature of the concentrated sulfuric acid to choose the gasket; the medium, temperature, and pressure are all important factors, as well as the strength of the bolts. . . . . The gasket selection for a medium varies in each case.
As mentioned above, the medium, temperature, and pressure determine which type of gasket should be used. Polytetrafluoroethylene is a fairly common choice. If the preload pressure is low, expanded PTFE sheets can be considered; they are slightly more expensive, but PTFE can withstand temperatures up to 260 degrees. In practice, a temperature of around 100 degrees is usually sufficient. It was also mentioned that metal wound gaskets and fluororubber gaskets can be used as well. The most important factor is the specific operating conditions; it’s useful to learn from each other and improve together.
For your operating conditions, modified polytetrafluoroethylene gaskets are suitable; I do not recommend the use of expanded PTFE or rubber+PTFE gaskets. The reason is that expanded PTFE tends to creep and relax, while rubber-PTFE gaskets have limited ability to repair flanges and are prone to leakage. The gasket referred to by your chief engineer should be a pure polytetrafluoroethylene gasket, which has high hardness and good corrosion resistance, but is prone to leakage.