Leakage issue of gaskets in the three-valve assembly for instruments in the hydrogenation reactor
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The gasket used in the pressure remote transmission three-valve assembly of the paraffin oil hydrogenation reactor was a PTFE gasket, and leakage occurred during operation. Question: Under high temperature and pressure in a hydrogen-containing environment, what type of gasket is suitable? Are copper gaskets suitable for use in hydrogen-rich environments?
Currently, it is necessary to know the pressure and temperature levels in your equipment. PTFE also comes in various types; pure tetrafluoroethylene can easily get damaged under such conditions. Graphite or glass fiber can be added to improve its durability. Our needle valves can withstand temperatures of up to 300°C and pressures of up to 200 MPa in hydrogen environments, while they can handle pressures of up to 400 MPa in non-high-temperature conditions. Therefore, it is essential to choose the appropriate material based on the actual application requirements.
The outlet flow meter FT1111A of hydrogen feed pump A uses a Rosemount 3051 high-static-pressure differential pressure transmitter and a high-pressure three-valve assembly; the medium is crude oil (wax oil), with an operating temperature of 180°C and an operating pressure of 18.8 Mpa. The gasket selected is a PTFE+graphite gasket resistant to high-temperature creep ； The temperature in the hydrogenation reactor is even higher than this, and it involves hydrogen. Leaks occurred in both locations.
For ordinary PTFE materials, the temperature tolerance is usually around 120 degrees Celsius; use graphite wound gaskets, as they can withstand high temperatures
Because it is a relatively narrow sealing groove, wound gaskets cannot be used. Can copper gaskets and aluminum gaskets be used? Is there a possibility of hydrogen embrittlement under high-temperature hydrogen?
Copper gaskets will do; I’ve never seen aluminum ones used in high-temperature environments.