The pressure in the closed pipeline increases unintentionally
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A gasoline pipeline about 4 meters long, with valves at both ends closed, thus in a sealed state (the pipeline is not heated and is not insulated); the pressure inside it kept rising during the night, and pressure was released back into the tank on several occasions. It’s unclear where this pressure came from I personally suspect it is due to the saturated vapor pressure; at that time, the temperature of the material was 24°C, while the nighttime ambient temperature was 16°C. Could someone help explain this?
Is it related to changes in volume caused by changes in metal temperature?
This is the only explanation available for now; it depends on whether there is a large temperature difference, as well as the saturated vapor pressure of the material
If the pipeline is filled with material, its saturated vapor pressure is low; therefore, when the inlet and outlet are closed, a pressure much higher than the system’s design pressure will be generated. The solution usually involves installing a thin pressure relief pipe or a safety valve on the material pipeline.
1) Measure the tank wall temperature； 2) Is there internal leakage in the valve? ； 3) Saturated vapor pressure
This post was last edited by wang*neng on 2022-10-24 at 19:44. If the entire pipe is filled with a liquid phase and both ends are sealed, an increase or decrease in temperature can lead to an increase in pressure. A decrease in temperature causes volume changes due to the thermal expansion and contraction of the pipe, while an increase in temperature results from the thermal expansion and contraction of the liquid; it depends on which has a larger coefficient of expansion. In the gas phase, pressure increases only when the temperature rises.
Could it be an internal valve leak? Are there other lines on the pipeline as well, not just the valves for cutting off materials?