What are the precautions for dry gas seals during a compressor emergency shutdown?
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During an emergency shutdown of the propylene compressor, when medium-pressure nitrogen (the sealing gas used during normal operation) cannot be supplied in a timely manner, the primary seal loses its effectiveness due to the decrease in pressure at the compressor outlet; as a result, the pressure difference across the dry gas seal decreases and the flow rate drops； Guys, how does your company handle this – by ignoring it (with the booster pump making automatic adjustments)? Should low-pressure nitrogen be used instead? ?
It would be best to include a simple diagram to facilitate discussion. Regarding the supply of sealing gas, multi-path supply should be adopted where conditions permit. A single air storage tank is provided to ensure continuous gas supply, for reference only.
After the compressor stops, the lubricating oil system cannot be shut down; therefore, it is sufficient to ensure normal supply of isolation gas, with a pressure of at least 0.05 Mpa
During an emergency stop, the pressure booster pump will start automatically; if there is no such pump, manual switching to medium-pressure nitrogen is required
Our coke oven gas compressor was shut down urgently; the dry gas seal operates by diverting the secondary sealing gas to medium-pressure nitrogen when the pressure of the process gas is less than or equal to that of medium-pressure nitrogen, while the isolation gas and the primary sealing gas always use medium-pressure nitrogen.
1. Post-isolation gas 2. Primary medium-pressure nitrogen 3. Be careful to prevent surge 4. Pay attention to lubricating oil
May I ask which manufacturer your propylene compressor self-pressurization device is from? Can the self-pressurization meet the requirements for the flow rate of the sealing gas when jumping out of the vehicle?
Is the self-pressurizing inlet for the dry gas seal of your propylene compressors located at the original seal gas pipeline location, or somewhere else?
Installed on the primary seal gas inlet pipeline
John Crane provides a matching American-made imported pneumatic reciprocating booster pump, which is used during startup and shutdown processes and can meet the requirements
We have an additional propylene self-pressurization system added by Sichuan Nikki Dry Gas Sealing Company; it is also connected to the inlet pipeline for the primary sealing gas. However, during the initial operation, self-pressurization was used and the flow rate of the sealing gas did not meet the minimum requirements, so it cannot be used at present. In cases of shutdowns or during initial operation, does it still necessary to switch to medium-pressure nitrogen as the sealing gas? I’m not sure how your self-pressurization is configured