A PSA nitrogen generation system mainly consists of an air compressor, an air purification system , an air storage tank,

A PSA nitrogen generation system mainly consists of an air compressor, an air purification system , an air storage tank, a switching valve , an adsorber, and an oxygen buffer.

It consists of containers, etc.

After being compressed by an air compressor, the raw air undergoes dust removal, oil removal, and drying before entering the air storage tank. It then passes through the left intake valve.

The air enters the left adsorption tower. At this point, the tower pressure increases, and nitrogen molecules in the compressed air are adsorbed by the zeolite molecular sieve, while unadsorbed oxygen molecules...

It then passes through the adsorption bed and enters the oxygen buffer tank via the outlet valve . This process is called adsorption and lasts for tens of seconds.

After the adsorption process is complete, the left and right adsorption towers are connected by a pressure equalization valve to bring the pressure in the two towers into equilibrium.

This process, known as pressure equalization, lasts approximately 3-5 seconds. After pressure equalization, the compressed air passes through the right intake valve and enters the right adsorption valve.

The adsorption process is repeated in the left adsorption tower. Simultaneously, the oxygen adsorbed by the molecular sieve in the left adsorption tower is depressurized and released into the atmosphere through the left vent valve.

In the gas, this process is called desorption, and the saturated molecular sieve is thus regenerated. Similarly, while the left column adsorbs, the right column simultaneously...

Desorption also occurs. After adsorption in the right column is complete, it enters the equalization process, and then switches to the left column for adsorption, repeating this cycle.

Continuous oxygen production.

The above basic process steps are all automatically controlled by PLC and automatic switching valves.

PSA nitrogen generators operate on the principle of pressure swing adsorption, using high-quality carbon molecular sieves as the adsorbent under a certain pressure.

Nitrogen gas is produced from the air under pressure. The purified and dried compressed air undergoes pressure adsorption and depressurization desorption in an adsorber.

Appendix. Due to the dynamic effects of air, the diffusion rate of oxygen in the micropores of carbon molecular sieves is much greater than that of nitrogen; therefore, oxygen is preferentially diffused by the carbon molecular sieve.

Adsorption occurs, where nitrogen is enriched in the gas phase to form the final nitrogen gas. Then, the pressure is reduced to atmospheric pressure, and the adsorbent desorbs the adsorbed nitrogen.

Impurities such as oxygen are removed to achieve regeneration. Typically, two adsorption towers, A and B, are set up in the system; one tower adsorbs nitrogen and the other removes impurities.

The regeneration process involves controlling the opening and closing of pneumatic valves via a control device to alternate the circulation of the two towers, thereby achieving continuous production of high-quality nitrogen.

The purpose.

The process flow diagram of the PSA nitrogen generation system is shown in Figure 1.

The air compressor in Figure 1 is used to provide sufficient air volume and a relatively constant input pressure (0.75 ~ 0.8 MPa) of raw material air.

After purification treatment by a refrigerated dryer to remove water, oil, and solid particles, a constant output of nitrogen gas is achieved.

The system is equipped with two adsorption towers, A and B, which operate alternately. Pure compressed air from the air supply system is controlled by an electromagnetic pneumatic valve.

Y1 and Y2 enter the adsorption tower A from the lower part. They are adsorbed by the carbon molecular sieve bed within the adsorption tower and gradually move upwards.

During the process, oxygen molecules from the air are adsorbed into the micropores of the carbon molecular sieve, while nitrogen is concentrated in the gas phase and flows out from the top of the tower.

The nitrogen gas enters the nitrogen storage tank via electromagnetic pneumatic control valves Y6 and Y8; this process constitutes nitrogen production via adsorption in tower A. Simultaneously, adsorption tower B...

Application of PLC in nitrogen generators

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The adsorbed oxygen molecules are discharged via electromagnetic pneumatic control valve Y5, meaning that column B desorbs to atmospheric pressure. Columns A and B operate alternately.

Nitrogen supply continues. When the adsorption capacity of the carbon molecular sieve in tower A reaches equilibrium, the tower immediately stops adsorption. At this time, Y1,

Y4, Y5, and Y8 are all in the off state, while Y2, Y3, Y6, and Y7 are simultaneously in the on state. Two adsorption towers, A and B, are used.

After pressure equalization, the system switches to adsorption in tower B and desorption in tower A. At this time, compressed air enters through electrical control valves Y1 and Y3.

The nitrogen gas enters the lower part of adsorption tower B and is adsorbed by the carbon molecular sieve bed in tower B. The separated nitrogen gas enters the nitrogen storage tank via Y7 and Y8.

Nitrogen is produced by adsorption in tower B. Towers A and B alternate in adsorption and desorption, thus continuously supplying nitrogen to the nitrogen storage tank.

The operating sequence and switching time of the Y1-Y8 electrical control valves are all controlled by the PLC, ensuring a continuous supply of power to the two towers.

Nitrogen gas.

The automatic loop process during normal operation is as follows:

Press the program start button → Refrigerated dryer starts → Delay X seconds → Empty air conditioner starts → Delay X seconds → Enter adsorption A → Delay X seconds

→Equal pressure A=B→Delay X seconds→Adsorption of B delayed X seconds→Equal pressure B=A→Delay X seconds→Re-enter adsorption of A, and so on.

The system will cycle continuously; press the stop button. The entire system will then stop working.

1. + indicates that the valve is in the open state;
2. When the equal pressure A=B and the equal pressure B=A, it will open X seconds later than Y?Y;
3. The delay time X seconds should be set arbitrarily between 0 and 99.9 seconds.

The control system requires both manual and automatic operation modes, and it is also required that valves Y1-Y8 can be checked in manual mode.

The air compressor and refrigerated dryer can be started and stopped manually and independently ;

B=A indicates the activation status of the four stages Y1-Y8; each operation should be indicated by an indicator light. During automatic operation, it should be able to...

It operates according to the requirements of the automated process flow and can display the corresponding working status in the simulated process flow diagram. Simultaneously, it monitors the automated operation.

All delay times during the process must be adjustable and the current delay setting value must be displayed and queried in real time.