Basic process flow of PSA nitrogen production

After being compressed by the air compressor, the air enters the air storage tank after undergoing dust removal, oil removal, and drying. It enters the left adsorption tower through the air intake valve and the left suction inlet valve. The tower pressure rises, and the oxygen molecules in the compressed air are adsorbed by the carbon molecular sieve. The unadsorbed nitrogen passes through the adsorption bed and enters the nitrogen storage tank through the left suction outlet valve and nitrogen gas generation valve. This process is called left suction, and lasts for tens of seconds.

After the completion of the left adsorption process, the left adsorption tower and the right adsorption tower are connected through the upper and lower pressure equalizing valves to equalize the pressure of the two towers. This process is called pressure equalizing and lasts for 2-3 seconds. After pressure equalizing, compressed air enters the right adsorption tower through the air intake valve and the right suction valve. Oxygen molecules in the compressed air are adsorbed by carbon molecular sieves, and enriched nitrogen enters the nitrogen storage tank through the right suction valve and nitrogen production valve. This process is called right suction, lasting for tens of seconds.

At the same time, the oxygen adsorbed by the carbon molecular sieve in the left adsorption tower is depressurized and released back into the atmosphere through the left exhaust valve. This process is called desorption. Conversely, when the left tower adsorbs, the right tower also desorbs.

In order to completely discharge the oxygen released by depressurization in the molecular sieve into the atmosphere, nitrogen is purged through a normally open back purge valve to purge the adsorption tower being desorbed, blowing the oxygen inside the tower out of the adsorption tower. This process is called blowback, and it occurs simultaneously with desorption.

After the right suction is completed, enter the pressure equalizing process, then switch to the left suction process, and continue the cycle.

The working process of the nitrogen generator is completed by controlling three two-position five-way pilot solenoid valves with a programmable controller, and then controlling the opening and closing of eight pneumatic pipeline valves with solenoid valves. Three two-position five-way pilot solenoid valves control the left suction, equalizing pressure, and right suction states respectively. The time flow of left suction, equalizing pressure, and right suction has been stored in the programmable controller. In the power off state, the pilot gas of the three two-position five-way pilot solenoid valves is connected to the closing port of the pneumatic pipeline valve. When the process is in the left suction state, the solenoid valve that controls the left suction is energized, and the pilot gas is connected to the opening ports of the left suction intake valve, the left suction production valve, and the right exhaust valve, allowing these three valves to open, completing the left suction process, while the right adsorption tower desorbs. When the process is in a pressure equalizing state, the solenoid valve that controls the pressure equalizing is energized, and other valves are closed; The pilot gas connects the opening ports of the upper and lower equalizing valves, allowing the two valves to open, completing the equalizing process. When the process is in the right suction state, the solenoid valve that controls the right suction is energized, and the pilot gas is connected to the opening ports of the right suction intake valve, the right suction production valve, and the left exhaust valve, allowing these three valves to open, completing the right suction process, while the left adsorption tower desorbs. In each process, except for the valves that should be opened, all other valves should be in the closed state.