The main components of air are nitrogen and oxygen. By utilizing the different adsorption properties of nitrogen and oxygen in air on zeolite molecular sieve (ZMS) at ambient temperature (oxygen can pass through while nitrogen is adsorbed), an appropriate process is designed to separate nitrogen and oxygen to produce oxygen. Nitrogen has a stronger adsorption capacity on zeolite molecular sieve than oxygen (nitrogen interacts more strongly with the surface ions of the molecular sieve). When air passes through an adsorption bed filled with zeolite molecular sieve adsorbent under pressurized conditions, nitrogen is adsorbed by the molecular sieve, while oxygen, being less adsorbed, is enriched in the gas phase and flows out of the adsorption bed, thereby separating oxygen and nitrogen to obtain oxygen. When the molecular sieve adsorbs nitrogen to near saturation, the air flow is stopped, and the pressure of the adsorption bed is reduced, allowing the adsorbed nitrogen to desorb, and the molecular sieve is regenerated for reuse. By alternating two or more adsorption beds, oxygen can be produced continuously.

The boiling points of oxygen and nitrogen are close, making them difficult to separate, and they tend to be enriched together in the gas phase. Therefore, pressure swing adsorption (PSA) oxygen generation units typically only produce oxygen with a concentration of 90-95% (the maximum oxygen concentration is 95.6%, with the remainder being argon), also known as oxygen-enriched air. In comparison, cryogenic air separation units can produce oxygen with a concentration of 99.5% or higher.

The adsorption bed of a pressure swing adsorption air separation oxygen generation unit must include two operational steps: adsorption and desorption. To continuously obtain product gas, oxygen generation units are typically equipped with two or more adsorption beds. Additionally, from the perspectives of energy consumption and stability, some necessary auxiliary steps are set up. Each adsorption bed generally undergoes steps such as adsorption, pressure release, evacuation or depressurization regeneration, purge displacement, and pressure equalization and repressurization, operating cyclically. At the same time, each adsorption bed is in a different operational step. Under the control of a PLC, they switch at timed intervals, coordinating the operation of several adsorption beds with staggered timing, ensuring the stable operation of the pressure swing adsorption unit and the continuous production of product gas. For the actual separation process, other trace components in the air must also be considered. Carbon dioxide and moisture generally have much stronger adsorption capacities on common adsorbents than nitrogen and oxygen. Suitable adsorbents can be added to the adsorption bed (or the oxygen generation adsorbent itself can be used) to adsorb and remove them.

The technical specifications of the VPSA oxygen generator are as follows↓↓:

◆Product scale: 100-10000 Nm3/h

◆Oxygen purity: ≥90-94%, adjustable within the range of 30-95% according to user requirements.

◆Oxygen production power consumption: When oxygen purity is 90%, the power consumption per unit of pure oxygen is 0.32-0.37 kWh/Nm3.

◆Oxygen pressure: ≤20 kPa (can be pressurized)

The VPSA oxygen generator uses a blower to intake and pressurize raw air and generally employs lithium molecular sieve.

The single-unit gas production capacity of a VPSA oxygen generator can reach 7500~9000 Nm3/h. Compared to PSA oxygen generators, VPSA oxygen generators have lower energy consumption (power consumption per cubic meter of oxygen produced ≤0.5 kWh) and are more environmentally friendly and green. For decades, Hangzhou Lecheng Gas Equipment Co., Ltd. has focused on the production of small and medium-sized air separation equipment, accumulating extensive research, development, and production experience. For more technical information about VPSA industrial oxygen generators, please feel free to call for consultation.