Regarding the setting pressure of the safety valve
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The large capacity specifications and those for 150 state only that the setting pressure of the safety valve shall not be greater than the design pressure, and it shall be determined using the maximum allowable operating pressure. But there is one problem, which is a common issue encountered during testing. Many companies purchase equipment designed for high pressures and use it in applications with lower pressure levels. For example, they buy equipment designed for a pressure of 2 MPa, but in actual operation only about 0.5 MPa is used; consequently, the setting pressure of the safety valve is adjusted to 0.5 MPa. Is this okay? It doesn’t seem there’s any rule stating that it’s not allowed. My question is: what parameters should be used to determine the set pressure for pressure vessels?
It does not violate the regulations and standards.
1. The setting pressure of a safety valve is generally determined based on the design pressure or the maximum allowable operating pressure, with the design pressure itself usually being determined based on the maximum operating pressure. 2. When enterprises purchase pressure vessels, the working pressure (0–1.5 MPa) is generally specified; the design pressure (2.0 MPa) is determined by designers based on the operating conditions, rather than by the purchaser. 3. If a high-pressure pressure vessel is purchased (with a design pressure of, for example, 2.0 MPa), it can be used with equipment rated for 0.5 MPa; this has little to do with the setting pressure of the safety valve. 4. If the safety valve is intended to keep the actual operating pressure at or below 0.5 MPa, a pressure relief valve (set at 0.5 MPa) can be installed on the pipeline. It is advisable not to adjust the setting pressure of the safety valve, as its parameters are clearly specified in the as-built drawings; if any changes are made, the original design team should be informed at least.
1. Chemical processing equipment is custom-made; it is not purchased from the market, but is designed and manufactured according to the customer’s specifications. 2. It is necessary to clarify the relationship and sequence among the design pressure, the setting pressure of the safety valve, and the operating pressure – the operating pressure (or maximum operating pressure) exists first. ) This is specified by the customer’s requirements; based on these conditions, the set pressure of the safety valve is determined according to the rules, and then the design pressure is determined based on that set pressure. 3. The set pressure for in-service pressure vessels shall be as specified in the drawings. Pressure vessels come with as-built drawings upon leaving the factory; if a safety valve is installed, the setting pressure of that valve is indicated on the drawings. I can’t figure out the order of your thinking.
I think there’s always a safety margin; by constantly learning from work experience, it might just save your life at a critical moment
Previously, for processes where the operating pressure was less than 1 MPa, the set pressure of the safety valve was equal to the process operating pressure plus 0.1 MPa. For processes where the operating pressure was greater than 1 MPa, the set pressure of the safety valve was equal to the process operating pressure multiplied by 1.1.
A setting pressure of 0.5 for the user is not incorrect, but it can cause the safety valve to activate frequently; it would be better to set it 0.1 Mp higher than the operating pressure.
According to Clause B.4.7 of Appendix B to Part 1 – General Requirements of GB150, when the equipment is equipped with a safety valve, the design pressure of the container is determined step by step, which is in line with the view stated in point 2 on page 4.
What’s strange about that? Most furnaces for sulfur operate at pressures of a few kPa to several dozen kPa; the design pressure of such furnaces is set at 0.3 to 0.5 MPa, and the strength of these furnaces is calculated accordingly
During regular inspections, as long as the setting pressure of the safety valve complies with the specifications, it is acceptable; this situation you mentioned is often encountered during such inspections