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

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

 

The pressure swing adsorption nitrogen generator is an automatic equipment that uses carbon molecular sieve as the adsorbent and uses the principle of pressure adsorption and desorption to absorb and release oxygen from the air, thereby separating nitrogen. Carbon molecular sieve is a kind of columnar granular adsorbent covered with micropores on the surface and inside, which is black, The pore size distribution of carbon molecular sieves enables the kinetic separation of oxygen and nitrogen. Such a pore size distribution allows different gases to diffuse into the micropores of the molecular sieve at different rates without repelling any gas in the mixed gas (air). The separation effect of carbon molecular sieves on oxygen and nitrogen is based on the small difference in the dynamic diameter of the two gases. The dynamic diameter of oxygen molecules is small, so there is a faster diffusion rate in the micropores of carbon molecular sieves, and the nitrogen molecules have a smaller kinetic diameter. The kinetic diameter is larger and thus the diffusion rate is slower. The diffusion of water and carbon dioxide in compressed air is not much different from that of oxygen, while the diffusion of argon is slower. What is finally enriched from the adsorption tower is a mixture of nitrogen and argon. After long-term use, the micropore diameter of carbon molecular sieve will change; if the compressed air contains moisture and oil, it will also affect the micropore diameter of carbon molecular sieve, thereby affecting the performance of nitrogen production, resulting in a decrease in nitrogen purity. Therefore, the nitrogen generator needs regular maintenance.