https://en.wikipedia.org/wiki/Cryogenic_gas_plant
A cryogenic gas plant is an industrial facility that creates molecular oxygen, molecular nitrogen, argon, krypton Helium and Xenon at relatively high purity. As air is made up of nitrogen, the most common gas in the atmosphere, at 78%, with Oxygen at 19%, and Argon at 1%, with trace gasses making up the rest, Cryogenic gas plants separate air inside a distillation column at cryogenic ...