What is the unit for the water content in nitrogen?
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We usually say that the purity of nitrogen is 99.9% or more, with multiple 9s, but how is the water content in nitrogen expressed? Is it the water content per KG of nitrogen, or the water content of nitrogen per m3?
The nitrogen content is expressed in mg/L or mg/m3
The specific moisture content is generally not stated; instead, the dew point is used to indicate the relative level of moisture； If it is necessary to specify the exact water content, PM is commonly used to indicate it ；
What was said on floor 3L is correct, but what are the specific figures? Who can explain it?
The purity of nitrogen refers to the fact that it may contain elements such as oxygen in addition to nitrogen. The water content of nitrogen is expressed in ppm, with ppm generally referring to mass or volume concentration. PPM denotes the mass of solute contained in one million units of solution by mass; a value expressed as a fraction of a million is referred to as X PPM
It can be expressed using the dew point, for example, -65 degrees Celsius, or in PPM (parts per million). There is a relationship between the dew point and PPM; you can search for a conversion table of dew points on Baidu~~
Similar to the moisture content in instrument air, the moisture content in nitrogen is expressed in terms of dew point; it can also be expressed in ppm. As mentioned on floor 7, the specific value varies depending on the requirements of the product. For example, if the required water content of nitrogen in a product is 10 ppm, this means that the water content should be below 10 mg/m3.
I also have a question. Assuming the nitrogen pressure of the product is 0.5 MPaG and the allowable water content is 10 ppm, which means less than 10 mg/m3, then should this value refer to the content under actual operating conditions or under standard conditions? @Ameba
The dew point varies even under standard pressure conditions. You can check the specific corresponding table.
Similarly, the PPM value for gases refers to either volume or molar percentage. When a gas at standard conditions is compressed, its moisture content (PPM) remains unchanged. As for dew point, it is necessary to distinguish between pressure dew point and atmospheric pressure dew point. At the same water content, the dew point under normal pressure (positive pressure) is higher than that at atmospheric pressure~~