Carbon molecular sieves and zeolite molecular sieves are commonly used in the field of nitrogen and oxygen production.
The separation effect of molecular sieve on oxygen and nitrogen is mainly based on the difference in the diffusion rate of these two gases on the surface of molecular sieve. Carbon molecular sieve is a carbon-based adsorbent with some characteristics of activated carbon and molecular sieve. Carbon molecular sieve has a very small micropore composition, with a pore size distribution between 0.3nm and 1nm. Gas with a smaller diameter (oxygen) diffuses faster and enters the solid phase of the molecular sieve more, so that the gas phase can be enriched in nitrogen. After a period of time, the adsorption of oxygen by the molecular sieve reaches equilibrium. According to the different characteristics of carbon molecular sieve for adsorbing gas under different pressures, reducing the pressure makes the carbon molecular sieve release the adsorption of oxygen. This process is called regeneration. The pressure swing adsorption method usually uses two towers in parallel, alternately performing pressure adsorption and decompression regeneration, so as to obtain a continuous nitrogen flow.
