I would like to ask about some issues encountered when using steam pressure regulators
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As shown in the diagram, a pressure regulator with a setting of 0.8 MPa before the valve and 0.5 MPa after the valve is currently in use. Some problems have arisen during operation, and I would like to ask for advice from everyone. Specifically, the equipment’s gas consumption has decreased, and overpressure often occurs after the valve, causing the safety valve to activate. How can this be resolved?
The relief valve’s setting pressure is too low! Adjust the main pipeline pressure and the pressure of the safety valve at the point of use.
Pressure relief valves have flow-pressure correlation parameters, although many manufacturers do not provide them. If the flow is reduced by half and the pressure rise is less than 20% of the set value, it can meet most requirements (i.e., under conditions of reduced load). I think the valve size is too large. Furthermore, the constant-load PCV with a regulator has pressure that is less affected by load changes. In the figure below, there are two forms of PCV: flow-pressure diagrams.
Judging from the picture, the pressure relief valve has a fixed setting; there is no pressure increase, and the outlet pressure should not exceed 0.5 Ma. Therefore, the activation of the safety valve should have nothing to do with this valve.
The pressure relief valve has a poor seal; it should be disassembled for inspection or replaced. Or the pressure relief valve is too large.
For the reduced gas consumption of the device you described, is it before the valve or after the valve? Is it 0.8 or 0.5? In many places, there are multi-level steam piping systems; without clarifying this issue, any discussion is meaningless. If the gas consumption of the equipment ahead of the valve decreases, the safety valve will activate because the pressure relief valve was sized too small. A decrease in the gas flow rate after the valve indicates that the pressure reducing valve is too large. The solutions are also different. As can be seen from the diagram, the actuator of your pressure relief valve is significantly larger than necessary; in other words, you chose a too large one. The main reason for the safety valve to activate is likely the fact that when there are changes in the flow rate downstream of the valve, the actuator does not adjust with sufficient precision, resulting in overpressure downstream of the valve. Also, the first time I saw a Y-filter, it was installed as shown in the picture. It doesn’t work at all.
If the downstream system is used intermittently, once no gas is required, the PCV will leak internally, and the pressures on the upstream and downstream sides will equalize. As a result, at regular intervals, the differential pressure causes the safety valve to activate once
Indeed. For example: if the liquid level in the storage tank remains constant but the nitrogen seal valve leaks, the PSV will activate.