What causes frosting in the pipeline behind the oxygen control valve?
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When introducing oxygen, it was found that the pipeline behind the oxygen control valve was frosted. Does anyone know what’s causing this? How should it be dealt with?
Refrigeration by pressure reduction allows the air separation unit to raise the oxygen temperature further.
It is caused by endothermic expansion under reduced pressure; administer it slowly, and if it’s really strong, use industrial hydrolysis for freezing.
Throttling effect: When the volume of a gas increases and its pressure decreases, heat is absorbed; conversely, heat is released.
Perhaps the oxygen introduction and venting speed was a bit too high, the amount of vented gas was also somewhat large, and the venting time was a bit long. Oxygen introduction and venting are generally carried out as the final step before feeding; it should not be done too early. Doing so too early not only leads to frosting but also results in significant waste of oxygen.
Frosting occurs as a result of a drop in temperature; from the equation PV=nRT, it can be seen that temperature is affected by a decrease in pressure. Therefore, oxygen should not be introduced too early
It is recommended to reduce the oxygen pressure; this is caused by an insufficient flow rate. It’s also possible that the diameter of the vent valve is too large, resulting in too low an oxygen supply level
Control valve, pipes \ Frosting: When gas changes from high pressure to low pressure, its volume increases, absorbing a large amount of heat; this leads to a drop in the temperature of the surrounding air, causing the water vapor in the air to condense.
The oxygen temperature is too low; increase the oxygen temperature
Following the typical throttling expansion principle, the flow control valve functions as a throttle valve when introducing oxygen.