PSA Nitrogen Generator Valve Time Cycle
Core Principle of PSA Nitrogen Generator Valve Time Cycle:
The PSA (Pressure Swing Adsorption) nitrogen generator achieves continuous nitrogen production through the alternate adsorption and regeneration of two towers. The valve time cycle refers to the sequence of opening and closing of pneumatic valves controlled by a PLC program, enabling the adsorption tower to complete the cycle of "adsorption - equal pressure - desorption - re-equal pressure". The typical cycle is 60 to 180 seconds (variations may exist depending on the design of different manufacturers), and the core objective is to balance nitrogen purity, production volume, and the lifespan of the carbon molecular sieve.
Key stages and valve operations (taking the dual-tower system as an example):
Adsorption stage (30 to 90 seconds)
Valve status: Inlet valve open, gas production valve open, pressure equalization valve closed, exhaust valve closed.
Process: Compressed air enters Tower A, where carbon molecular sieve adsorbs impurities such as O₂ and CO₂, and N₂ is output from the top of the tower to the buffer tank. At this time, Tower B is in the desorption state.
Pressure equalization stage (5 to 15 seconds)
Valve status: Pressure equalization valve is open, intake valve and exhaust valve are closed.
Process: Tower A (high pressure) and Tower B (low pressure) are connected through the pressure equalization valve. The pressure is balanced to recover energy and reduce pressure fluctuations during switching.
Desorption stage (30 - 90 seconds)
Valve status: Exhaust valve is open, reverse blowing valve is open (optional), intake valve and gas production valve are closed.
Process: The pressure of Tower A is reduced to normal pressure. The impurities such as O₂ adsorbed are released through the exhaust valve. At the same time, some pure nitrogen gas is blown back to clean the molecular sieve, accelerating the regeneration process.
Equalization pressure stage (5 to 15 seconds)
Valve status: Pressure equalization valve is open, while other valves are closed.
Process: B tower (after adsorption completion) supplies gas to A tower to raise the pressure of A tower, preparing for the next round of adsorption.
Relationship between cycle and purity:
The longer the cycle (such as 180 seconds), the more fully the molecular sieve adsorbs, and the higher the nitrogen purity. However, the equipment volume and energy consumption may increase; conversely, a short cycle (60 seconds) is suitable for high production and low purity scenarios.
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