Cryogenic air separation processes are used to divide atmospheric air into three pure gaseous elements – nitrogen (N2), oxygen (O2), and argon (Ar).
Further separation can also produce quantities of noble gases such as neon, krypton, and xenon, but the first three elements listed are the products most commonly required by industry, particularly as ultra-high purity (UHP) gases for the semiconductor manufacturing sector.
Accurate analysis of gas concentrations across the process supports improved process control, safety, and optimal product quality. Purity measurements ensure the gas products are of the required specifications. For example, the typical bulk gas composition for nitrogen is for the gas to contain less than 10 parts-per-million (ppm) of oxygen. Oxygen usually needs to be better than 99.5% pure, while argon must contain fewer than 10 ppm impurities.
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