Air is a homogeneous mixture of different gases such as oxygen, nitrogen, carbon dioxide, etc. It can be separated by the process of fractional distillation.Fractional distillation is a separation method where the difference in boiling points of components is used to separate the liquid mixture into fractions through distillation. The process begins with the liquefaction of air. Other methods such as membrane, pressure swing adsorption (PSA) and vacuum pressure swing adsorption (VPSA) are commercially used to separate a single component from ordinary air. Pressure swing adsorption (PSA) is a technology used to separate some gas species from a mixture of gases under pressure according to the species’ molecular characteristics and affinity for an adsorbent material, it operates at near-ambient temperatures.