Oxygen peak compressed air after switching drying tower

[MaxPlanck]

Hello,

We have a problem regarding the drying of compressed air using a twin tower system with purge air for regeneration. As desiccant a 13X molecular sieve is applied.

We notice an increase of oxygen in the air composition after switching from the saturated tower to the regenerated tower. Oxygen content raises to about 26%, and after a short time it drops back to its normal value of 20.96%.

How can this phenomenon be explained?

Best regards

 

[zdas04]

That sounds like your mole sieve has a much higher potential to adsorb oxygen than nitrogen at elevated temperature than at normal temperature. So when you heat up the air to cook off the water, you have more than normal oxygen on the adsorption sites and less than the normal nitrogen on the sites. Cooling the bed back off with normal temperature gas causes the bed to come back into equilibrium and gives up the extra oxygen.

The magnitude and duration of your spike sounds like this is what is happening to you.

David