I: Classification of nitrogen generators（Classification and characteristics by separation method）：

1. Membrane separation method: direct preparation, pipeline transportation, continuous gas supply, simple operation (low purity, technology needs to be improved).

2. Pressure swing adsorption (PSA): direct preparation, pipeline transportation, continuous gas supply, simple operation (long life, high purity).

3, cryogenic method: (1) direct use, like a large steel mill.

                                   (2) Production of liquid nitrogen. Some gas stations are gasified, bottling to the user (                                                  discontinuous) deep cooling technology, complex operation.

Industry valve application：

PSA pressure swing adsorption nitrogen generator principle：

    The principle of PSA pressure swing adsorption nitrogen generator is mainly based on the adsorption rate of oxygen and nitrogen by carbon molecular sieve. The carbon molecular sieve preferentially adsorbs oxygen, while the nitrogen is mostly concentrated in the non-adsorbed phase. The carbon molecular sieve itself has a characteristic that the adsorption capacity for oxygen increases when pressurized, and the amount of adsorption of oxygen during decompression decreases. By utilizing the characteristics of this pressure swing adsorption, the separation of oxygen and nitrogen is achieved, and the gas components we need are obtained. Since the adsorbent has a certain adsorption capacity, it needs to be regenerated when the adsorption is saturated. Therefore, the adsorption of the single adsorption bed is intermittent. To ensure continuous gas supply, the adsorption is alternately carried out in parallel by the double adsorption tower, and one tower is operated while the other is regenerated to achieve continuous nitrogen production.