Atmospheric air contains 78% nitrogen, 21% oxygen, and 1% other gases.
Oxygen is a “fast” gas and is selectively diffused (permeated) through the membrane wall while nitrogen is allowed to travel along the inside of the fiber, thus creating a nitrogen rich product stream.
The oxygen enriched gas, or permeate, is vented from the membrane separator at atmospheric pressure, while the nitrogen is piped from the outlet for further pressure and flow controll.
The Oxygen content in the produced nitrogen, is mainly a factor of feed-air pressure and nitrogen flow. But temperature also have some influence.
-Increasing the flow rate will increase oxygen content in the product gas.Higher nitrogen flow, higher oxygen content.
-Decreasing the flow rate will decrease the oxygen content in the product gas.Lower nitrogen flow, lower oxygen content.
-Feed Air pressure increases the productivity of the membranes.
The relationship is illustrated in the following graph:
This relationship is important to keep in mind when troubleshooting a system that deviate from original spesifications. It could be as easy as adjusting feed-pressure or flow. Knowledge to this could save time and frustration to a system that could need re-tuning.