|
Pressure Swing Adsorption (PSA) technology relies on the selective adsorption phenomena of gas molecules under pressure on the surface of highly porous and efficient adsorbent. Here in oxygen generation, the adsorbent is zeolite based molecular sieve (Z.M.S).
Process of PSA Oxygen Gas Generators
In this system, when compressed air is passed through a adsorption tower field with Z.M.S, the molecules of oxygen, moisture & other unwanted gases are adsorbed on surface of Z.M.S and oxygen which is not adsorbed by Z.M.S comes out of adsorption tower. This oxygen is collected in a surge vessel. Two adsorption towers are used for continuous generation of oxygen gas, which are interconnected with autochange over valves controlled by Programmable Control Panel (PLC) in the control panel. After saturation of one tower with oxygen, the process automatically changes over to another tower resulting into the continuous production of oxygen gas for long.
The Stages:
- In the first molecular bed, compressed air is fed in which nitrogen is trapped and oxygen flows out.
- When the first bed is filled with nitrogen, air flows into the second bed.
- When the second bed separates oxygen from nitrogen, nitrogen is vented out in the atmosphere in the first bed.
- Again the compressed air flow in to the first bed, the process continues and there is a constant flow of oxygen.
In fact, the productivity of a PSA oxygen generator depends upon the requirement of oxygen purity. With a relatively small increase in feed air these generators can produce significantly more oxygen at 90% purity than it can at 95.4%. By means of a PLC or some other micro processor based controller, on larger generators it is practical for the users to change the swing cycles on timely basis. In fact, the purity and flow levels can also be selected and optimized based on changing demand variables.
Flow Scheme for PSA Oxygen Gas Generators




