The working principle of PSA oxygen production equipment

Industrial oxygen generator is an automatic equipment that uses zeolite molecular sieve as the adsorbent and uses the principle of pressure adsorption and decompression desorption to adsorb and release oxygen from the air, thereby separating oxygen. Zeolite molecular sieve is a kind of spherical granular adsorbent with micropores on the surface and inside, which is processed by a special pore type treatment process, and it is white. Its pore type characteristics enable it to realize the kinetic separation of O2 and N2. The separation of O2 and N2 by zeolite molecular sieve is based on the small difference in the dynamic diameter of these two gases. N2 molecules have a faster diffusion rate in the micropores of zeolite molecular sieve, and O2 molecules have a slower diffusion rate. The diffusion of water and CO2 in compressed air is not much different from that of nitrogen. The final enrichment from the adsorption tower is oxygen molecules. The pressure swing adsorption oxygen production is based on the selective adsorption characteristics of the zeolite molecular sieve. It adopts the cycle of pressure adsorption and decompression desorption to make compressed air alternately enter the adsorption tower to achieve air separation, thereby continuously producing high-purity product oxygen.

    1. compressed air purification group

    The compressed air provided by the air compressor is first introduced into the compressed air purification components. The compressed air is first removed from the pipeline filter to remove most of the oil, water, and dust, and then the freeze dryer is used for further water removal, fine filter removal, and dust removal. And it is deeply purified by the ultra-precision filter that follows it. According to the operating conditions of the system, UAE Gas has specially designed a set of compressed air degreaser to prevent possible trace oil penetration and provide adequate protection for the molecular sieve. The rigorously designed air purification components ensure the service life of the molecular sieve. The clean air treated by this component can be used for instrument air.

    2. air tank

    The function of the air storage tank is to reduce the air flow pulsation and play a buffering effect; thereby reducing system pressure fluctuations, allowing compressed air to smoothly pass through the compressed air purification components to fully remove oil and water impurities and reduce the load of the subsequent PSA oxygen and nitrogen separation device. At the same time, when the adsorption tower is switching, it also provides a large amount of compressed air for the PSA oxygen-nitrogen separation device to quickly increase the pressure in a short time, so that the pressure in the adsorption tower will quickly rise to the working pressure, ensuring the reliability and stability of the equipment run.

    3. oxygen and nitrogen separation device

    There are two adsorption towers A and B equipped with special molecular sieve. When the clean compressed air enters the inlet end of the A tower and flows through the molecular sieve to the outlet end, N2 is adsorbed by it, and the product oxygen flows out from the outlet end of the adsorption tower. After a period of time, the molecular sieve in Tower A is saturated by adsorption. At this time, tower A automatically stops adsorption, compressed air flows into tower B to absorb nitrogen and produce oxygen, and regenerate the molecular sieve of tower A. The regeneration of the molecular sieve is achieved by rapidly lowering the adsorption tower to atmospheric pressure to remove the adsorbed N2. The two towers alternately perform adsorption and regeneration, complete oxygen and nitrogen separation, and continuously output oxygen. The above process is controlled by a programmable controller (PLC). When the oxygen purity of the gas outlet is set to the value, the PLC program acts, and the automatic vent valve opens to automatically vent the unqualified oxygen to ensure that the unqualified oxygen does not flow to the gas point. When the gas is vented, the muffler is used to muffle the noise to make the noise less than 75dBA.

    4, oxygen buffer tank

    The oxygen buffer tank is used to balance the pressure and purity of the oxygen separated from the nitrogen and oxygen separation system to ensure the continuous supply of oxygen is stable. At the same time, after the adsorption tower is switched, it will backfill part of the adsorption tower with its own gas, on the one hand, it helps the adsorption tower to increase the pressure, and also plays a role in protecting the bed, which plays a very important process in the working process of the equipment. Supporting role.

The PSA oxygen generator is based on the principle of pressure swing adsorption, using high-quality zeolite molecular sieves as adsorbents to produce oxygen from the air under a certain pressure. The purified and dried compressed air is subjected to pressure adsorption and decompression desorption in the adsorber. Due to the aerodynamic effect, the diffusion rate of nitrogen in the pores of the zeolite molecular sieve is much greater than that of oxygen. Nitrogen is preferentially adsorbed by the zeolite molecular sieve, and oxygen is enriched in the gas phase to form product oxygen. Then, after decompression to normal pressure, the adsorbent desorbs the adsorbed nitrogen and other impurities to realize regeneration. Generally, two adsorption towers are installed in the system. One tower absorbs oxygen and the other tower desorption regeneration. The PLC program controller controls the opening and closing of the pneumatic valve, so that the two towers alternately circulate to achieve the purpose of continuous production of high-quality oxygen. . The entire system consists of the following components: compressed air purification components, air storage tanks, oxygen and nitrogen separation devices, and oxygen buffer tanks; if steel cylinders need to be filled, oxygen boosters and bottle filling devices are installed at the end.