Why is interlocking installed for the flare discharge pressure in dry gas seals?
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I don’t understand what the relationship is between primary sealing and flare discharge pressure; please advise
A high pressure at the primary flare indicates that the primary seal is no longer functioning properly, resulting in significant leakage of process gas; therefore, an interlock system must be installed
A high pressure at the primary flare indicates that the sealing performance at the primary stage is poor; this may be due to issues with the moving and stationary components or the pressure of the gas supply. Interlocks are installed to protect the dry gas seal system from damage
The pressure interlock is designed to prevent massive leaks of process gas due to damage to the dry gas seal; everything mentioned above is correct.
For pipelines used for sealing and venting, a two-choice interlock based on flow rate or pressure is generally installed. Its purpose is that once the unit is operating normally and the supply of air to the secondary seal is stable, if an over-limit alarm is triggered by the flow meter on the vent line, and at the same time the corresponding pressure switch also gives an alarm, it indicates that the seal at that end may be damaged; in such a case, the operation should be stopped, and the seal at that end should be removed and inspected.
In the case of a series-connected dry gas seal, most of the gas flowing through the flare line is secondary seal gas, with a small portion being primary seal gas. If, with the inlet pressure of the secondary seal remaining constant, both the flow rate and pressure of the gas flared are too high, it indicates that there is significant leakage of primary seal gas, and the primary seal surface may be damaged; in such a situation, the system must be shut down. If the flare flow rate is too low while the inlet pressure of the secondary seal remains unchanged, it indicates that there is excessive leakage of air from the secondary seal; the sealing surface of the secondary seal may be damaged, and in such a case, the machine must also be shut down!
For safety reasons, prevent large-scale leaks of process gases.
It is generally high linkage or low linkage.
A high pressure in the torch indicates that the primary sealing is not effective; the sealing gas is leaking out. If the pressure becomes too high, it can damage the main seal. Interlocks are installed to prevent the dry gas sealing system from being damaged
The amount of gas discharged is generally composed of the leakage from the primary seal and the emissions from the secondary seal. If the air intake to the secondary seal remains stable, an increase in leakage indicates that the primary seal is leaking more heavily; such a high level of leakage suggests that the dry gas seal surface has been damaged. To prevent further damage to the rotating and stationary rings or other components, an interlock shutdown is initiated as a corrective measure.
The characteristic of this interlock system is as follows: detection (measurement of the pressure in the primary sealing chamber), alarm (triggered when pressure exceeds the set value), interlock action (activated when pressure reaches its limit), and discharge (an instruction is sent to open the relief valve for emergency pressure release).