When introducing high-pressure, low-temperature NG for the first time, how should the pipeline pressure be increased?
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If high-pressure natural gas is introduced into the system safely, the pressure of the gas is 70 bar and the temperature is 5 degrees； The pipelines and equipment connected downstream have all been purged with nitrogen, maintaining a slight pressure of 0.5 bar. It is well known that high voltage drops can cause a very large temperature drop ； It can easily cause water separation and freezing on the outer wall of the pipeline ； How can we effectively control the impact of this temperature drop, and how can voltage be adjusted in a gradual manner? I hope that technical experts can provide reasonable solutions. :Lol, the image below is a simplified version; it’s roughly divided into 3 sections, and each section contains valves that can be used, not just the 2 shown in the image. It’s simply used for differentiation.
A pressure equalizing valve should be added to that natural gas isolation valve; before introducing natural gas, this small valve is opened to pressurize the downstream pipeline. The less gas that is depressurized, the less heat is absorbed during that process, allowing for heat exchange with the surrounding environment. This prevents the temperature of the depressurized gas from dropping too much, which could otherwise lead to freezing and blockages.
This pressure equalizing valve is likely to freeze over quite soon
If the flow rate you operate at is low, the heat absorbed during pressure reduction is minimal; as a result, the valve itself can exchange heat with the surrounding air, thereby keeping the gas temperature constant； If you enable your main valve to control a very small opening, it is also possible to achieve a smaller reduction in gas temperature
Okay, thank you! :handshake
I have an immature idea: what should be the pressure control target downstream of the V2 valve? Control the pressure behind valve V1 to the average of the air supply pressure and the target pressure behind valve V2, and then gradually open valve V2
I have an immature idea: what should be the pressure control target downstream of the V2 valve? Control the pressure behind valve V1 to the average of the air supply pressure and the target pressure behind valve V2, and then gradually open valve V2
Yes, increase the voltage of the system in stages； Ultimately, the pressure of the entire system becomes consistent with that of the air source.