What Are The Specifications for The Principle, Flow Rate, And Purity of PSA Nitrogen Generators?

PSA (Pressure Swing Adsorption) nitrogen generators are high-purity nitrogen production devices based on pressure swing adsorption technology, widely used in industries such as manufacturing, electronics, food processing, and chemicals. Their operating principle involves using carbon molecular sieves to selectively adsorb nitrogen and oxygen from air, thereby achieving nitrogen separation and purification. The following is a detailed explanation of the principle, flow rate, and purity of PSA nitrogen generators.

1. Working Principle of PSA Nitrogen Generators

The core principle of PSA nitrogen generators is to use carbon molecular sieves (CMS) to selectively adsorb nitrogen and oxygen from the air. Under high-pressure conditions, oxygen molecules, due to their smaller diameter and faster diffusion rate, are more easily adsorbed by carbon molecular sieves, while nitrogen molecules enter the microporous structure of the molecular sieves to a lesser extent. Therefore, nitrogen is enriched under high pressure, while oxygen is adsorbed within the molecular sieves. When the system pressure decreases, the adsorbed oxygen is released, completing the regeneration process of nitrogen. This process is achieved by alternating operation of two adsorption towers (Tower A and Tower B), enabling continuous nitrogen production.  

1. Adsorption Stage  

Under high pressure, air is compressed and fed into the adsorption tower, where oxygen is adsorbed onto the molecular sieves, while nitrogen is discharged from the adsorption tower. At this point, the molecular sieves in the adsorption tower have adsorbed a large amount of oxygen, and nitrogen becomes the product gas.

2. Pressure Reduction Stage

When the pressure inside the adsorption tower decreases, the adsorbed oxygen begins to desorb from the molecular sieves and enters the venting system. At this point, nitrogen continues to be discharged from the adsorption tower into the buffer tank.  

3. Flushing Stage

After the pressure reduction stage, the adsorption tower needs to be flushed to remove residual oxygen and moisture. The flushing process is typically controlled by a regulating valve to ensure the molecular sieve's service life and nitrogen purity.

4. Pressure-building stage

After flushing is complete, the adsorption tower is pressurised again to prepare for the next adsorption cycle. At this point, air re-enters the adsorption tower, oxygen is adsorbed, and nitrogen continues to be discharged.

II. Flow Specifications of PSA Nitrogen Generators

The flow rate of a PSA nitrogen generator refers to the amount of nitrogen produced by the generator per unit of time, typically expressed in standard cubic metres per hour (Nm³/h). Depending on the model and application, the flow rate range of PSA nitrogen generators can vary from a few Nm³/h to several thousand Nm³/h. For example:

Flow rate range: 1–3000 Nm³/hr, suitable for laboratories, small workshops, food preservation, laser cutting, welding, electronics manufacturing, chemical, metallurgy, and oil and gas industries.

III. Purity Specifications of PSA Nitrogen Generators

The purity of a PSA nitrogen generator refers to the percentage of oxygen or other impurities in the nitrogen gas. Depending on the application, the purity range of a PSA nitrogen generator can vary from 95% to 99.9995%. For example:

General industrial nitrogen: Purity of 95% to 99.5%, suitable for food preservation, injection moulding, rubber, and other industries.

High-purity nitrogen: Purity ranges from 99.9% to 99.9995%, suitable for industries such as semiconductor manufacturing, electronic component protection, and pharmaceutical production.  

1. Purity Grades  

95%: Suitable for general industrial applications, such as food preservation and injection moulding.  

99.5%: Suitable for industries with higher purity requirements, such as electronics manufacturing and chemicals.

99.9%: Suitable for industries with high purity requirements, such as semiconductor manufacturing and pharmaceutical production.

99.99%: Suitable for industries with high purity requirements, such as aerospace and precision manufacturing.

99.9995%: Suitable for industries with ultra-high purity requirements, such as semiconductor manufacturing and laboratory analysis.

2. Dew Point

The dew point refers to the temperature at which moisture in nitrogen reaches saturation, typically expressed as the dew point at standard atmospheric pressure. The dew point range of PSA nitrogen generators can vary from -40°C to -70°C, depending on the type of molecular sieve and process flow.

3. Other Technical Parameters of PSA Nitrogen Generators

In addition to flow rate and purity, other technical parameters of PSA nitrogen generators include:

Exit pressure: Typically 0.05 to 0.8 MPa, adjustable according to actual requirements.

Energy consumption: High-efficiency, energy-saving PSA nitrogen generators have low energy consumption, with energy savings of up to 10% to 30%.

Operating conditions: Including ambient temperature, humidity, and atmospheric pressure ranges; high-quality equipment can operate stably under a wide range of conditions.

Service life: High-quality PSA nitrogen generators can last over 20 years and come with quality guarantees for major components.

Control method: Typically equipped with a PLC control system to achieve automated operation and monitoring, enhancing the stability and convenience of the equipment.

Maintenance convenience: Considerations include installation space, maintenance cycles, and ease of maintenance. A well-designed system should be easy to install and maintain.