The Working Principle of Oxygen-Generating Molecular Sieves

The core working principle of oxygen-generating molecular sieves is based on the Pressure Swing Adsorption (PSA) technology. It leverages the molecular sieve's high selective adsorption property for nitrogen gas. Through a cyclic process of pressurized adsorption and depressurized desorption, the separation of oxygen and nitrogen is achieved. The specific process includes four key steps: air compression, pretreatment, adsorption separation, and molecular sieve regeneration.

1.Air Compression and Pretreatment

Air is first pressurized to 0.5-0.7 MPa by a compressor. It is then cooled by a cooler and removes moisture via refrigerated dryers, forming clean, compressed air. This step provides a stable gas source for subsequent adsorption separation and prevents moisture from affecting the molecular sieve's performance.

2. Adsorption Separation Process

The main components of air are nitrogen (accounting for about 78%) and oxygen (about 21%). Although their molecular sizes are similar (the kinetic diameter of nitrogen molecules is about 0.364 nm, and that of oxygen molecules is about 0.346 nm), they differ in chemical properties. The pretreated air enters the adsorption tower filled with molecular sieves. The microporous structure of the molecular sieve preferentially adsorbs nitrogen, while oxygen, due to its smaller kinetic diameter and slower diffusion rate, is enriched and output as product gas. At this point, the oxygen purity can reach more than 90%.

3.Molecular Sieve Regeneration and Cycling

Once the molecular sieve becomes saturated with adsorbed nitrogen, it is regenerated by depressurizing it to release the nitrogen, restoring its adsorption capacity. The system typically employs a dual-tower or multi-tower design, where towers alternately perform adsorption and desorption to enable continuous oxygen production. The working cycle of each tower includes five stages: adsorption, pressure reduction, cleaning, regeneration, and pressurization.