A nitrogen generator is a device used to separate and produce high-purity nitrogen from the air. Its working principle is mainly based on the following technologies: pressure swing adsorption (PSA), membrane separation, and cryogenic separation. The common and widely used technology is pressure swing adsorption (PSA). The following is an introduction to the working principle and different technologies of a nitrogen generator:

1. Pressure swing adsorption (PSA) technology

Working principle:

Pressure swing adsorption (PSA) technology is based on the differences in adsorption characteristics of different gas molecules in the air on adsorbents, and separates nitrogen and oxygen by changing pressure conditions. The main process includes the following steps:

Air compression: Air is compressed to a higher pressure (usually 7-10 bar) through an air compressor.

Pre treatment: Compressed air passes through filters and dryers to remove moisture, oil mist, and impurities, ensuring the purity of the air entering the adsorption tower.

Adsorption: The dried air enters the adsorption tower, which is filled with carbon molecular sieve (CMS). Under high-pressure conditions, carbon molecular sieves preferentially adsorb oxygen, water vapor, and carbon dioxide from the air, while nitrogen is separated through an adsorption bed.

Desorption: When the adsorption capacity of the adsorption tower reaches saturation, the system switches to a low-pressure state, releasing impurities such as adsorbed oxygen. Alternating circulation: Nitrogen generators are usually equipped with two or more tower systems. Through alternating operation, one tower adsorbs and the other tower works separately, thereby continuously and stably producing nitrogen.

Advantages:

Energy saving: No need for high temperature and high pressure conditions.

Easy to operate: high degree of automation and convenient operation.

Low maintenance cost: The main components have a long lifespan and are easy to maintain.

2. Membrane separation technology

Working principle:

Membrane separation technology utilizes the differences in diffusion rates of different gas molecules in membrane materials to achieve gas separation. The specific process is as follows:

Air compression and pretreatment: Similar to PSA technology, air is compressed and dried to remove impurities.

Membrane separation: The pre treated air passes through the membrane separation module. The membrane material has a higher permeation rate for oxygen, carbon dioxide, and water vapor, while the permeation rate for nitrogen is lower. By selectively permeating the membrane, oxygen and other impurities are removed to obtain high-purity nitrogen gas.

Advantages:

The equipment is simple and compact: it occupies a small area.

Easy to operate: Start and stop quickly.

Suitable for small-scale and medium-sized nitrogen demand.

3. Deep cold separation technology

Working principle:

Deep cryogenic separation technology is based on the difference in boiling points of various components in the air under low temperature conditions, through low-temperature liquefaction and gas separation. The specific process is as follows:

Air compression and pretreatment: Similar to the first two technologies, air is compressed and dried.

Deep cold separation: Compressed air gradually cools to a low temperature (below -180 ℃) in a multi-stage expander and liquefies into liquid air. Then, oxygen, nitrogen, and other inert gases are separated through a distillation tower.

Advantages:

High purity: can produce high-purity nitrogen gas (above 99.999%).

Suitable for large-scale industrial production: able to meet large-scale nitrogen demand.

The nitrogen generator adopts different separation technologies and selects appropriate technical solutions according to application requirements and scenarios. Among them, pressure swing adsorption (PSA) technology has the advantages of energy conservation, simple operation, and low maintenance cost. Membrane separation technology is suitable for small-scale and medium-sized nitrogen demand, while cryogenic separation technology is suitable for situations that require high-purity nitrogen and large-scale industrial production.

By understanding these working principles and technical differences, it is easy to choose and use nitrogen generators to meet specific application requirements.