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he RDN series nitrogen generator is based on the principle of pressure swing adsorption, using high-quality carbon molecular sieves as adsorbents to produce nitrogen from air under a certain pressure. Purified and dried compressed air is subjected to pressurized adsorption and depressurization desorption in an adsorber. Due to aerodynamic effects, the diffusion rate of oxygen in the micropores of carbon molecular sieves is much faster than that of nitrogen. Oxygen is preferentially adsorbed by carbon molecular sieves, and nitrogen is enriched in the gas phase to form finished nitrogen gas. Then, after being depressurized to normal pressure, the adsorbent desorbs impurities such as oxygen, achieving regeneration. Generally, two adsorption towers are set up in the system, one tower adsorbs to produce nitrogen, and the other tower desorbs for regeneration. The PLC program controller controls the opening and closing of the pneumatic valve, causing the two towers to cycle alternately to achieve the goal of continuously producing high-quality nitrogen. The entire system consists of the following components: compressed air purification component, air storage tank, oxygen nitrogen separation device, and nitrogen buffer tank.

1. Compressed air purification component

The compressed air provided by the air compressor is first introduced into the compressed air purification component. The compressed air is first removed by a precision filter to remove most of the oil, water, and dust. Then, it is further removed by a freeze-drying machine, refined filter to remove oil, dust, and deeply purified by an activated carbon filter immediately following it. According to the system operating conditions, Red Gas has specially designed a set of compressed air oil removers to prevent possible trace oil infiltration and provide sufficient protection for carbon molecular sieves. The well-designed air purification components ensure the service life of carbon molecular sieves. The clean air treated by this component can be used for instrument air.

2. Air storage tank

The function of an air storage tank is to reduce airflow pulsation and play a buffering role; This reduces system pressure fluctuations and allows compressed air to pass smoothly through the compressed air purification component, fully removing oil and water impurities, and reducing the load on the subsequent PSA oxygen nitrogen separation device. At the same time, during the operation switching of the adsorption tower, it also provides a large amount of compressed air for the PSA oxygen nitrogen separation device to quickly boost pressure in a short period of time, causing the pressure inside the adsorption tower to quickly rise to the working pressure, ensuring the reliable and stable operation of the equipment.

3. Oxygen and nitrogen separation device

There are two adsorption towers equipped with dedicated carbon molecular sieves, A and B. When clean compressed air enters the inlet end of Tower A and flows through the carbon molecular sieve towards the outlet end, O2, CO2, and H2O are adsorbed by it, and the product nitrogen flows out from the outlet end of the adsorption tower. After a period of time, the carbon molecular sieve in Tower A is saturated with adsorption. At this point, Tower A automatically stops adsorption, compressed air flows into Tower B for oxygen absorption and nitrogen production, and the molecular sieve of Tower A is regenerated. The regeneration of molecular sieves is achieved by rapidly lowering the adsorption tower to atmospheric pressure to remove adsorbed O2, CO2, and H2O. The two towers alternate for adsorption and regeneration, completing oxygen nitrogen separation and continuously outputting nitrogen. The above processes are all controlled by programmable controllers (PLCs). When the purity value of nitrogen gas at the outlet is set, the PLC program will automatically open the vent valve to automatically vent unqualified nitrogen gas, ensuring that unqualified nitrogen gas does not flow to the gas consumption point. When venting gas, use noise reduction to reduce the noise to less than 75dBA.

4. Nitrogen buffer tank

The nitrogen buffer tank is used to balance the pressure and purity of the nitrogen separated from the nitrogen oxygen separation system, ensuring a stable continuous supply of nitrogen. At the same time, after switching the operation of the adsorption tower, it will charge some of its own gas back into the adsorption tower, which not only helps to boost the pressure of the adsorption tower, but also plays a role in protecting the bed layer, playing an extremely important process auxiliary role in the equipment operation process.