Carbon molecular sieve utilizes its sieving properties to achieve the separation of oxygen and nitrogen. The main component is elemental carbon, with a black columnar solid appearance (diameter 1-2mm, height 2-5mm). Due to the presence of a large number of micropores (with a diameter of 4 angstroms) with strong instantaneous affinity for oxygen molecules, they are commonly used to separate oxygen and nitrogen from air, and then produce nitrogen through a pressure swing adsorption device.