Dry gas seal issues
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We have four identical compressors here, made by Shaanxi Gas Turbine. Dry gas seals from Chengdu Huaxin are used. A few days ago, the plant had to shut down due to maintenance needs, and 3 units were stopped. The fourth unit cannot be shut down because its primary seal, which is designed to prevent liquid from entering due to the presence of gas, has been damaged. On the second day, while driving the vehicle, there was a primary leakage in the compressor; the flow rate and pressure on the high-pressure side were all overreported. Since the system pressure was lower than that of nitrogen, the pressure at the secondary seal has now risen to match the system pressure. I was just wondering if anyone knows what the reason for this is or has encountered a similar issue.
Is the startup sequence correct? How are the primary seal gas, secondary seal gas, and isolation gas activated? Seals are prone to damage when subjected to reverse pressure
The medium is contaminated with liquid; the four units use the same medium, and all of them are damaged!
Since this shutdown was a short-term one, the nitrogen used for the dry gas seal was not shut off
After D broke down, all 3 units following it were operated using nitrogen. .
Was the medium thoroughly purged before replacing it with nitrogen?
What is primary seal gas? Isn’t it the process gas after filtration? When using a dry gas seal, it is essential to ensure that there is pressure inside the machine; if there is no pressure, the flow of seal gas at the secondary level will create counterpressure on the seal, which can easily lead to damage to the main seal
At least 10 minutes before bringing the lubricating oil system into operation, isolate gas should be introduced first; nitrogen is used as the primary sealing gas. Once the flow rate in the flare line is approximately zero, the secondary sealing gas is introduced. The compressor must be started under pressure, with the pressure inside it being higher than the flare pressure by a certain amount – otherwise the seals are prone to damage. Once the pressure at the compressor outlet exceeds the pressure of the nitrogen used for primary sealing, the primary sealing gas can then be replaced with process gas
Is the gas used for your level 1 seal gas nitrogen or process gas?
Double-end face seal? When the seal is damaged, all the nitrogen enters the unit, which is probably the cause