How does the PSA nitrogen generator achieve adsorbent regeneration?

The scientific principle of the decompression desorption step in the PSA nitrogen generator is based on the basic theory of physical adsorption. Physical adsorption refers to the adsorption of gas molecules on the solid surface, and its adsorption force mainly comes from the van der Waals force between the gas molecules and the solid surface. In the PSA nitrogen generator, the adsorbent (such as activated carbon molecular sieve) has a large number of microporous structures, which provide adsorption sites for oxygen molecules. When compressed air enters the adsorption tower, oxygen molecules are selectively adsorbed on the microporous surface by the adsorbent due to their higher polarity and molecular size, while nitrogen is able to pass through the adsorbent layer due to its weaker polarity and smaller molecular size, thereby achieving nitrogen and oxygen separation.

However, as the adsorption process continues, the adsorption sites on the adsorbent surface will gradually be occupied by oxygen molecules until they reach saturation. At this point, if no intervention is made, the adsorption tower will lose the ability to continue to separate the gas. In order to restore the adsorption capacity of the adsorbent, a decompression desorption step must be performed. The basic principle of decompression desorption is to reduce the pressure in the adsorption tower, thereby breaking the physical adsorption balance between oxygen molecules and the adsorbent. During the decompression process, as the pressure decreases, the partial pressure of oxygen molecules in the gas phase also decreases, resulting in a weakening of the interaction force between oxygen molecules and the adsorbent surface. When this interaction force weakens to a certain extent, the oxygen molecules will be desorbed from the adsorbent surface and carried out of the adsorption tower with the airflow, thereby achieving the regeneration of the adsorbent.

In the actual operation of the PSA nitrogen generator, the decompression desorption step is usually closely linked to the switching of the adsorption tower. The PSA nitrogen generator usually contains two or more adsorption towers, which alternately perform adsorption and decompression desorption operations to ensure the continuous output of nitrogen. When an adsorption tower reaches saturation, the system automatically switches to another adsorption tower for adsorption, while reducing the pressure in the saturated adsorption tower and starting the decompression desorption process.

The specific operations of the decompression desorption process include:
Adsorption tower switching: When it is detected that the adsorption tower reaches saturation, the system automatically switches to another adsorption tower for adsorption operation, and closes the inlet valve and outlet valve of the saturated adsorption tower.

Pressure release: Open the pressure release valve of the saturated adsorption tower to gradually reduce the pressure in the adsorption tower to the set decompression desorption pressure. During the decompression process, oxygen molecules are desorbed from the adsorbent surface and carried out of the adsorption tower with the air flow.
Purge and regeneration: In order to further improve the regeneration efficiency of the adsorbent, some advanced PSA nitrogen generators also adopt a purge step. After decompression desorption, the adsorption tower is purged with an inert gas (such as nitrogen) or air to remove residual oxygen molecules and impurities. The purge process can further promote the regeneration of the adsorbent and improve the output efficiency and purity of nitrogen.
Pressure recovery and preparation for the next adsorption: After completing the decompression desorption and purge steps, close the purge gas valve and gradually restore the pressure in the adsorption tower to the adsorption operating pressure. At this point, the adsorption tower is ready for the next adsorption operation.

The decompression desorption step plays a vital role in the PSA nitrogen generator. It not only restores the adsorption capacity of the adsorbent, ensures the continuous output of nitrogen, but also improves the output efficiency and purity of nitrogen. Therefore, decompression desorption has a wide range of application value in modern industry.

Chemical industry: In the chemical production process, nitrogen is often used as a protective gas and a reaction inert gas. The continuous, high-purity nitrogen provided by the PSA nitrogen generator can ensure the stability and safety of the chemical production process. The decompression and desorption step ensures the continuous regeneration of the adsorbent, thereby ensuring the continuous supply of nitrogen.
Electronic manufacturing industry: In semiconductor manufacturing, PCB board production and other links, nitrogen is widely used to prevent oxidation reactions and protect product quality. The PSA nitrogen generator ensures the purity and stability of nitrogen through an efficient decompression and desorption step, meeting the high requirements of the electronics manufacturing industry for nitrogen.
Food industry: As an inert gas, nitrogen plays an important role in food preservation. The nitrogen provided by the PSA nitrogen generator can extend the shelf life of food and maintain the quality of food. The decompression and desorption step ensures the continuous supply of nitrogen, providing a reliable source of nitrogen for the food industry.
Pharmaceutical industry: In pharmaceutical production, nitrogen is used in many aspects such as drug packaging and gas protection. The nitrogen provided by the PSA nitrogen generator can ensure the drying, sterilization and cooling of medicines, improving the quality and safety of medicines. The vacuum desorption step ensures the purity and stability of nitrogen, meeting the high requirements of the pharmaceutical industry for nitrogen.
Other fields: In addition to the above fields, PSA nitrogen generators are also widely used in non-ferrous smelting, electricity, laboratories and scientific research. In these fields, the vacuum desorption step also plays an important role, ensuring the continuous supply and high-quality output of nitrogen.