Working Principle Of PSA Nitrogen Making Machine

1, basic knowledge


1, gas knowledge: nitrogen is the most abundant gas in the air, which is inexhaustible. It is colorless, tasteless and transparent, belonging to a subinert gas and does not maintain life. High purity nitrogen is often used as a protective gas for isolation of oxygen or air. Nitrogen (N2) content in the air was 78.084% (volume of various gases in the air were divided into: N2:78.084%, O2:20.9476%, CO2:0.0314%, AR: 0.9364%, H2, CH4, and other N2O, O3, SO2 and NO2, but the content is extremely low), the molecular weight of 28, boiling point: -195.8 degrees, condensation point C: -210.


2. pressure knowledge: pressure swing adsorption (PSA) nitrogen process is pressurized adsorption, atmospheric desorption, the use of compressed air. The best adsorption pressure of carbon molecular sieve used now is 0.75~0.9MPa, and the gas in the whole nitrogen system is pressure and has impact energy.

2, the working principle of PSA nitrogen


PSA nitrogen making machine is an automatic device for separating nitrogen from the air and adsorbing and releasing oxygen from air by using carbon molecular sieve as adsorbent and pressure adsorption and depressurization and desorption. Carbon molecular sieve is a kind of coal as the main raw material, after grinding, oxidation, molding, carbonization and machined pass special treatment process and the surface and inside of the cylindrical porous granular adsorbent was black, the hole distribution as shown below: the pore size distribution characteristic of the carbon molecular sieve the dynamic separation can be achieved O2, N2. Such pore size distribution can make different gases diffused to the micropores of molecular sieve at different rates, and will not exclude any gas in mixed gas (air). Carbon molecular sieve separation effect on O2 and N2 are tiny differences in dynamics of these two kinds of gas diameter based on dynamics of smaller diameter of the O2 molecule, which has faster diffusion rate in microporous carbon molecular sieve, N2 molecular dynamics of larger diameter, and slow diffusion rate. The diffusion of water in compressed air and CO2 is quite different from that of oxygen, but the diffusion of argon is slow. In the end, the mixture of N2 and Ar is enriched from the adsorption tower. Carbon molecular sieve adsorption characteristics of O2 and N2 can be directly reflected by the equilibrium adsorption curve and dynamic adsorption curve by the two adsorption curve can be seen, the increase of adsorption pressure, the adsorption capacity of O2 and N2 increased at the same time, the adsorption amount and O2 increased to a large number of. The adsorption period of PSA is short, and the adsorption capacity of O2 and N2 is far from equilibrium (maximum), so the difference of O2 and N2 diffusion rate makes the adsorption capacity of O2 much higher than that of N2 in a short time. Pressure swing adsorption nitrogen production is based on the selective adsorption characteristics of carbon molecular sieve. It adopts pressure adsorption, decompression and desorption cycle cycle to make compressed air alternately enter the adsorption tower (or single tower) to achieve air separation, so as to continuously produce high purity nitrogen products.