Calculation of pressure drop in the pipeline from the equipment outlet to the safety valve inlet
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Since the regulation requires that the pressure in the pipeline between the equipment outlet and the safety valve inlet be less than 3% of a specified value, I would like to calculate the pressure in this pipeline; I’m not sure what value to use for the flow rate The pipeline medium is 97# gasoline; the diameter of the pipe to be protected is DN500, while the diameter of the pipeline at the safety valve outlet is DN25. The length of the inlet pipeline is 3 m. The design pressure of the safety valve is 1.8 MPa, and the operating pressure of the pipeline is 0.3 MPa. This post was last edited by shushu8589 on 2008-11-19 at 14:41
After thinking about it for the whole morning, I realized that the safety valve was installed in my system to account for thermal expansion of the pipes. Since the temperature of the oil in the pipes rises slowly as a result of changes in air temperature, the inlet flow rate here is essentially 0. As long as the installation isn’t too extreme (that is, the pressure relief time does not exceed 5 seconds, a parameter related to the pressure testing of the pipe fittings), the flow rate here will be at least 0. 6 m/s is reasonable.
I agree with the view from the 3rd floor; this valve should be a thermal relief valve, used to address the issue of overpressure that can occur when the liquid in sections that might become sealed expands due to heat. As a result, the amount of fluid released is small, and the pressure is relieved quickly. Currently, safety valves of size 3/4×1 inch are commonly used for this purpose. Abroad, it is generally called a thermal relief valve
I also asked everyone some time ago to help me solve the problem of pressure drop. A solution was actually found.
The rated discharge capacity of this safety valve should be selected
Generally, pressure relief valves are added in the areas of closed tubes, especially to account for thermal expansion related to temperature. This method is often used in low-temperature equipment.