Why should nitrogen generator be maintained? Why does the purity of the nitrogen generator decrease?

- Apr 27, 2020-

The pressure swing adsorption nitrogen making machine is an automatic equipment that uses carbon molecular sieve as the adsorbent, uses the principle of pressurized adsorption, depressurization and desorption to adsorb and release oxygen from the air, thereby separating nitrogen.

Carbon molecular sieve is a kind of columnar granular adsorbent filled with micropores on the surface and inside. The pore size distribution characteristics of carbon molecular sieve make it possible to realize the dynamic separation of O2 and N2.

Such pore size distribution allows different gases to diffuse into the pores of the molecular sieve at different rates without repelling any gas in the mixed gas (air). The separation effect of carbon molecular sieve on O2 and N2 is based on the small difference in the dynamic diameter of the two gases. The dynamic diameter of O2 molecule is small, so there is a faster diffusion rate in the pores of carbon molecular sieve. The kinetic diameter is larger, so the diffusion rate is slower.

The diffusion of water and CO2 in compressed air is not much different from that of oxygen, while the diffusion of argon is slower. The final enrichment from the adsorption tower is a mixture of N2 and Ar. After long-term use, the pore size of the carbon molecular sieve will change; if the compressed air contains water and oil, it will also affect the pore size of the carbon molecular sieve, which will affect the performance of nitrogen production and lead to a decline in nitrogen purity. Therefore, the nitrogen generator needs regular maintenance.