Pressure swing adsorption nitrogen generatorUsing compressed air as raw material and utilizing the selective adsorption characteristics of carbon molecular sieves for nitrogen and oxygen, nitrogen and oxygen separation is achieved through a cyclic process of pressurized adsorption and depressurized desorption. The process flow can be divided into the following core steps:

1、 Raw gas pretreatment

Compressed air preparation

The air is compressed by an air compressor to 0.6-0.8MPa, forming high-pressure gas raw materials.

Multi stage purification

Cooling and water removal: Compressed air enters the air storage tank for natural cooling, resulting in the precipitation of liquid water and regular discharge.

Freeze drying: Using a refrigerated dryer to lower the dew point of the air to 2-10 ℃, removing most of the water vapor.

Precision filtration: Through three-stage filters (coarse filtration, fine filtration, activated carbon filtration), oil, dust, and small particles are removed to ensure that the air entering the nitrogen production unit has an oil content of ≤ 0.001Ppm and a dust particle size of ≤ 0.01 μ m.

IIPressure swing adsorption nitrogen generatorCore process of pressure swing adsorption

Adopting a dual tower parallel structure (Tower A, Tower B), the valve is automatically switched through PLC control to achieve continuous gas production:

Adsorption stage

A tower operation: Compressed air enters from the bottom of A tower, and carbon molecular sieves preferentially adsorb oxygen molecules (O ₂), water vapor (H ₂ O), and a small amount of carbon dioxide (CO ₂). Nitrogen (N ₂) accumulates in the gas phase due to slow diffusion rate and flows out from the top, entering the nitrogen buffer tank.

Adsorption time: The single tower adsorption cycle is usually 40-60 seconds, depending on the quality of the feed gas and nitrogen purity requirements.

Pressure equalization stage

Pressure balance: Before the adsorption saturation of tower A, open the pressure equalization valve between tower A and tower B, and introduce high-pressure nitrogen gas from tower A into tower B (just after desorption) to quickly balance the pressure between the two towers (about 2-3 seconds).

Efficiency improvement: The pressure equalization can recover some of the high-pressure gas energy, reduce compressed air consumption, and avoid the impact of direct pressurization of the B tower on the molecular sieve.

Desorption and regeneration stage

Desorption of tower A: Close the inlet valve of tower A and open the exhaust valve. The pressure inside the tower quickly drops to atmospheric pressure, and the adsorbed gases such as O ₂ and H ₂ O desorb and are discharged.

Preparation for adsorption in tower B: After desorption is completed, tower B has been pressurized to working pressure and then enters the adsorption stage, forming a cycle.

Blow regeneration (optional)

Deep regeneration: To thoroughly remove residual impurities from the pores of the molecular sieve, a small amount of qualified nitrogen gas (about 5% -10% gas production) is introduced from the nitrogen buffer tank, and the desorption tower is backwashed to further reduce the impurity content.

3、 Nitrogen post-treatment and output

Purity testing and control

The purity of the gas in the nitrogen buffer tank is detected in real-time by a nitrogen analyzer. If the purity meets the standard (usually ≥ 95%, can be adjusted to 99.999%), the product valve opens and nitrogen enters the storage tank; If the standard is not met, open the vent valve and release the gas until the purity is restored.

Flow and pressure regulation

By adjusting the nitrogen output pressure (0.1-0.7MPa adjustable) and flow rate (3-3000Nm ³/h) through the export pressure reducing valve and flow meter, different user needs can be met.

safety protection

The equipment is equipped with safety valves (with an opening pressure of 1.1-1.15 times the working pressure), pressure sensors, and alarm systems to monitor the pressure of the adsorption tower in real time and prevent overpressure operation.