Seeking help with compressor dry gas seal issues
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When is the appropriate time to introduce the primary seal gas in a centrifugal compressor?
Once the compressor rotor has started rotating, sealing steam can be applied; initially, external steam is used. When the compressor’s speed reaches its minimum operating speed, it can switch to using its own air leakage. If it is put into use too early, it may cause uneven preheating of the rotor and bending of the main shaft. Vibration increases.
In my opinion, it should be put into use when the compressor is overhauled and the casing is replaced. At that time, the primary seal gas is nitrogen, with the aim of ensuring that the dry gas seal does not come into contact with any impure gases inside the casing; moreover, there must always be a flow indication for the primary seal gas.
The primary dry seal can be put into use before starting the compressor, while the dry seals of the other stages should be activated before the lubrication system is established. This is how we have always operated.
Inject a layer of sealing gas before pressurizing the machine body!
After the centrifuge is purged, the dry gas seal is also cleaned thoroughly. Once the centrifuge has been pressed, the main gas for the dry gas seal is supplied. If the main sealing gas is supplied before pressing the centrifuge, nitrogen is used first; this causes a large amount of nitrogen to enter the centrifuge’s interior, thereby altering its operating conditions