System airtightness issue!
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Our company’s hydrogenation system (not hydrocracking, but a type of hydrogenation catalytic synthesis reaction) requires leak testing, but only low-pressure nitrogen (0.6MPA–0.8MPA) is available at the site; the operating pressure of the system is 1.2MPA. Should we use compressed air for the leak testing? Should I first seal it with nitrogen and then with hydrogen?
If only a hermetic method using nitrogen first followed by hydrogen is available, what are the precautions?
Nitrogen sealing is generally used; it has a low cost and good safety features!
If the compressed air pressure is high enough, compressed air can naturally be used for airtight sealing, followed by nitrogen displacement. Introducing hydrogen without ensuring airtightness is also a safety hazard.
Use hydrogen directly for the airtightness test, but the test pressure must be controlled.
Regardless of the medium’s airtightness, remember that before introducing hydrogen, it is essential to ensure that the oxygen content in the system is below 0.5%.
It is recommended to first purge with nitrogen, then seal with nitrogen, and finally use hydrogen. Using hydrogen directly poses too great a risk
In any case, the oxygen content in the system must be <0.5% before introducing hydrogen
You should first ensure airtightness using a compressed air system, then replace the air with nitrogen, and finally introduce hydrogen while ensuring airtightness. The operating pressure isn’t high; what’s important is tightness, as well as the process of replacement. If your system is small, you can also use a nitrogen cylinder or a liquid nitrogen tank to increase the pressure in the system.