Largely undetectable to humans and potentially of an immensely hazardous nature, nitrogen is utilised in a wide range of applications from medicine to meals for two, especially in its cryogenically cool liquid state.
Liquid nitrogen is inert, colorless, odorless, non-corrosive, non-flammable, and extremely cold. Nitrogen makes up the major portion of the atmosphere (78.03% by volume, 75.5% by weight), is inert and will not support combustion – however, it is not life supporting. Nitrogen is inert except when heated to very high temperatures where it combines with some of the more active metals, such as lithium and magnesium, to form nitrides.
It will also combine with oxygen to form oxides of nitrogen and, when combined with hydrogen in the presence of catalysts, will form ammonia. Aside from N2, nitrogen may be referred to as GAN or GN in its gaseous form, and LIN or LN in its liquid form.
Production process
Produced in large volumes in both gas and liquid form by cryogenic distillation, smaller volumes may be produced as a gas by pressure swing adsorption (PSA) or diffusion separation processes (permeation through specially designed hollow fibres). Cryogenic processes can produce very pure nitrogen, but adsorption and diffusion processes are typically used to make the lower purity product in relatively small amounts. This is attractive to users when purity is not critical and alternatives (purchase of bulk liquid nitrogen, cylinders of high pressure nitrogen, or local cryogenic production) are more expensive or impractical.
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