Design pressure of the spherical tank, maximum operating pressure, and relief valve setting pressure
Thread Content
There is a spherical tank containing liquid hydrocarbons as its internal medium. Its design pressure is 1.77 MPa, the maximum operating pressure is 1.4 MPa, and the setting pressure of the safety valve is 1.71 MPa. Is this setting reasonable? Are there any issues?
The starting pressure is excellent; the regulations require it not to exceed the maximum operating pressure.
It is completely possible, or it can also be based on the design pressure of the safety valve.
The design pressure can be slightly higher
This setup needs to be considered in two scenarios: 1. If a gas-tightness test is not required, then this approach is reasonable. 2. A gas-tightness test is required, in which case this choice is unreasonable. If a gas-tightness test is required, the test pressure should be the design pressure, and it is necessary to conduct the test with the safety accessories in place (see Article 4.8.3 of the Pressure Vessels Regulations). The problem arises because the set pressure of the safety valve is lower than the design pressure, which makes it impossible to carry out the gas-tightness test. In such cases, we generally specify that the maximum allowable operating pressure of the container be higher than the design pressure, with the safety valve set at a pressure between the design pressure and the maximum allowable operating pressure; this way, the requirements of the airtightness test can be met.
5th floor is correct! However, the set pressure of actual safety valves is generally slightly lower than the design pressure ； At the same time, the maximum allowable operating pressure and the maximum operating pressure are easily confused ；
When indicating the maximum allowable operating pressure, the maximum allowable operating pressure replaces the design pressure
I agree with the view from the 5th floor; there should be two different scenarios. However, under normal circumstances, hydrocarbon-based media should undergo a gas-tightness test.
How dare they still use spherical tanks with liquid hydrocarbons as the medium? Have you seen the news about the explosion in Rizhao, Shandong? Hehe
The maximum operating pressure mentioned here is not the maximum allowable operating pressure; now that the spherical tank has been built and put into use, it is unclear whether this is a problem.
If it has been put into use, it has already passed the airtightness test