Please share some understanding regarding PPM
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I’ve always remembered that PPM means one part per million. I’m still not quite sure about some things. For example: if there is a gas feed of 23,720 kg/h, and the water vapor content in it is 10 PPM, then how is the water content calculated? 23720*10/1000000=0.2372kg/h, is it calculated this way directly? I just don’t quite understand whether this represents a mass fraction or a molar fraction Or rather, another form of expression.
It’s calculated this way; it should be the mass fraction! !
For gases, ppm is often mg/Nm3
ppm means one part per million, so the same unit must be used for comparison; if it is molecules per kg/h, then kg/h should be used as the denominator. Generally, ppm is used for gases, and the unit is volume. For example, if the total volume is 100,000 m3/h and component A constitutes 10 ppm, then the volume of component A is 100,000 x 10/1,000,000 = 1 m3/h.
If the feed rate is 23,720 kg/h, it must first be converted to a volumetric flow rate (for this, the mixed molecular weight of the feed is required). Then multiply the volumetric flow rate by X10/1000000, and the result will be the volumetric flow rate of water vapor.
For gases, it is volume; for liquids, it is mass
PPM is a mass concentration, and LZ’s algorithm is correct. This way of phrasing arises from the convenience of analytical testing in the tender documents.