With air as the raw material, carbon molecular sieve as the adsorbent, the use of pressure swing adsorption principle, the use of carbon molecular sieve on oxygen and nitrogen selective adsorption and nitrogen and oxygen separation method, commonly known as PSA nitrogen machine. This method is a new nitrogen production skill developed rapidly in the 1970s.

The Carbon Molecular sieve nitrogen sail (CMS-PSA) is a gas separation device that uses carbon molecular sieve (Sieving, referred to as CMS) as the adsorbent and air as the raw material, and uses pressure swing adsorption principle to separate oxygen and nitrogen to produce high-purity nitrogen.

Carbon molecular sieve is coal as the main raw material, through the selection, destruction, molding, drying, activation, heat treatment and other processes of the surface of the highly efficient non-polar adsorbent filled with micropores, it is not the same for the adsorption of gas molecules with different molecular weights, and not the same kinetic diameter of gas molecules are adsorbed in the carbon molecular sieve micropores of the dispersion rate is not the same.

There is a co-adsorption of oxygen and nitrogen on carbon molecular sieve, and there is no significant difference in the equilibrium adsorption amount of oxygen and nitrogen under the same adsorption pressure. Therefore, it is difficult to complete the useful separation of oxygen and nitrogen by pressure changes alone.

Although the usual properties of oxygen and nitrogen are not very different, their kinetic diameters are not the same. Although both are smaller than carbon molecular sieves, oxygen molecules disperse hundreds of times faster than nitrogen molecules. This is because smaller molecules disperse faster.  Using the characteristics of oxygen and nitrogen adsorption in a short time, the program controller switches rapidly between the two identical adsorption towers according to the specific time program, and the oxygen is separated from the air by the pressure shift adsorption process of pressurized oxygen adsorption and depressurized oxygen desorption. The oxygen-containing waste gas is discharged from the exhaust gas outlet at the bottom of the tower, and nitrogen is enriched in the gas phase because of no or little adsorption and is continuously output in the form of product gas. Therefore, this skill is also known as "molecular sieve nitrogen rich technology", which is a speed type nitrogen production technology.

Compared with the traditional nitrogen production method, it has simple technical process, high degree of automation, fast gas production (15 ~ 30 minutes), low energy consumption, product purity can be adjusted in a large range according to user needs, convenient operation and protection, low operating cost, and strong equipment adaptability, so it is very competitive in nitrogen production equipment below 1000Nm3/h. More and more small and medium nitrogen users are looking forward to PSA nitrogen production has become the first choice for small and medium nitrogen users.