What is the temperature of natural gas at 25 MPa?
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At a gas filling station, where the gas storage wells are pressurized to 25 MPa, what happens to the temperature? Does it become low?
When natural gas is pressurized from atmospheric pressure to 25 MPa, its temperature certainly rises, but cooling is generally required during the compression process (most gas compression systems are equipped with cooling systems); cooling may be sufficient to bring the temperature back to normal levels. Therefore, there is no fixed relationship between the pressure and temperature of a gas (unlike the saturated vapor pressure of liquids).
The density of compressed natural gas at standard conditions is 0.7174 Kg/m3; what is its density at 20 MPa or 25 MPa? In other words, how is the quality of natural gas storage wells determined? For wells with a volume of 3 cubic meters and a pressure of 20 MPa to 25 MPa
Density at standard conditions × Absolute pressure (MPa) / 0.1 = Density. Last edited by lcp_1217 on 2009-3-22 18:49]
What value should be used for the absolute pressure here?
To compress natural gas to 25 MPa, work must be done on the gas, which increases its internal energy; this increased internal energy raises the temperature of the gas. If it is desired to prevent the temperature from rising, the gas needs to be cooled in order to dissipate the increased internal energy. The density under standard conditions is calculated as: density = density at standard conditions × absolute pressure (MPa) / 0.1. Of course, this absolute pressure refers to gauge pressure plus the standard atmospheric pressure.
When compressed to 20 Mpa, work is done on it from the outside, so its temperature definitely rises; however, a cooling system is usually used to lower its temperature to room temperature before it is sent to the gas well. If there is no pressure in the gas well, the temperature will drop upon throttling, depending on the actual conditions. I’m not sure if this is correct; please give me some advice.