Severe condensation in the nitrogen pipeline
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This post was last edited by Xin Zai Tian Bian on 2018-9-11 at 22:16. As the title suggests, during the startup of the installation, nitrogen was used to pressurize and displace air from the system; the pipeline with diameter 20 mm was connected to the pipeline at the container’s inlet (diameter 150 mm). When 18 kilograms of nitrogen were used to pressurize a system that contained around 2 kilograms of gas, severe condensation occurred on the surface of the pipe segment located about one meter away from the connection point on the 20 mm diameter pipeline, with water droplets falling down continuously. Please explain!
This post was last edited by ylb913 on 2018-9-12 at 12:28. The 18 kilograms of nitrogen at the beginning were not vaporized sufficiently; subsequently, vaporization under reduced pressure caused significant heat absorption and temperature drop.
It’s very easy to understand. This is the Joule-Thomson effect: when a gas is compressed and then expanded through throttling, its temperature drops, resulting in a cooling effect. Nitrogen at 18 bar at room temperature is throttled to 2 bar. The temperature will drop, causing dew or frost to form on the pipes after throttling.
The high-pressure nitrogenizer freezes even in the middle of summer
What was said on the 4th floor is more accurate. It’s nitrogen at 1.8 MPa at room temperature, not liquid nitrogen; therefore, it’s incorrect to say that vaporization absorbs heat. High-pressure nitrogen absorbs heat as it expands under reduced pressure, which leads to cooling of the surrounding environment, resulting in sweating, frosting, or icing of the pipelines – this is a normal phenomenon.
At room temperature and 1.8 Mpa, it is impossible for liquid nitrogen to exist. If there is liquid nitrogen, at this pressure the temperature must be -160 degrees.
With a isenthalpic change under reduced pressure and work done on the system, the temperature naturally decreases
It is related not only to air humidity but also to the amount of air you use. The principle seems similar to that of refrigeration: it absorbs heat from around the tube walls, causing the moisture in the air to condense