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Pressure Swing Adsorption, on-site nitrogen gas generation

One of the core technologies in many nitrogen gas generators today is Pressure Swing Adsorption (PSA), using Carbon Molecular Sieve (CMS) adsorbent. The PSA process using CMS is a highly efficient method of generating high purity nitrogen gas from compressed air.

What are PSA and CMS?

PSA is an air separation technique that allows the separation of a gas mixture into its individual components by using a solid medium, in this case CMS, to which part of the gas mixture preferentially adsorbs under pressure.

The CMS is essentially a bed of small carbon beads. When a nitrogen purification column packed with CMS is pressurised with atmospheric air (mainly consisting of nitrogen, oxygen and argon) and moisture, oxygen and moisture are adsorbed by the carbon beads whereas nitrogen is not. This occurs because of the angstrom size of nitrogen and oxygen molecules – the CMS pores are exactly the right size to allow oxygen to enter and adsorb, whereas the nitrogen molecules are too large and pass through the purification column.

PSA-nitrogen generator

PSA using CMS diagram

The PSA process consists of a two stage cycle;

  1. The Adsorption stage, where oxygen, H2O, and CO2 molecules in compressed air are adsorbed into the porous structure of the CMS whilst nitrogen molecules pass through the column and into a storage vessel.
  2. The Regeneration stage where the pressure normalises via rapid depressurisation and the adsorbed molecules are vented to the atmosphere.

This process requires a constant temperature, which is as close to an ambient as conditions will allow (20-25 deg C).

Peak Scientific produce several PSA generators including several of our best-selling Genius series to our Precision Nitrogen and Hydrogen generators for GC as well as our whole of lab solution, i-FlowLab.

To find out more about Peak's PSA generators    






Related Post: Read about the advantages of PSA nitrogen generators here.

Laboratory nitrogen hydrogen

Peak Scientific laboratory gas generators

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Mr. Misao Iwata - 04/10/2016 03:47
Dear Sirs,

Would you, please, give me a technological comment of whether or not your company
are able to fabricate the PSA units to adsorb and desorb CO2 from flue gas stream?

I am very thrilled at your comment.

I look forward to receiving your comments as quickly as possible.

Thank you very much, indeed.

With the best regards.
Bruce Peat - 04/10/2016 07:55
Dear Mr Misao Iwata,

To ensure the best quality and purity of nitrogen output we always recommend that the inlet gas meets ISO8753-1:2010 Class 1.4.1. We would not recommend the use of flue gas which does not meet this standard to supply our compressorless nitrogen generators.

A breakdown of this standard is below:

Class 1 Particulate
In each cubic metre of compressed air, the particulate count should not exceed 20,000 particles in the 0.1-0.5 micron size range, 400 particles in the 0.5-1 micron range and 10 particles in the 1-5 micron size range.

Class 4 Water
A pressure dew point (PDP) of +3 degrees C or better is required and no liquid water is allowed.

Class 1 Oil
In each cubic metre of compressed air, not more than 0.01mg of oil is allowed. This is a total level for liquid oil, oil aerosol and oil vapour.

If you have any further questions please let us know by leaving a comment or you can use the following link to contact us:

Kind Regards,

wahyu hidayat - 09/05/2018 05:27
Dear Sir,

I want to ask about the regeneration of Molecular sieve in PSA. Would you mind giving method how to remove/release the adsorbate (CO2) from the adsorbent (Molecular Sieve)?
I look forward to receiving your answer as soon as possible

thank you very much
bmcbride - 09/05/2018 08:10
Dear Mr Wahyu Hidayat,

Thank you for your question.

I can confirm that on depressurisation of the CMS columns, adsorbed gases, primarily O2, but also CO2 (which makes up 0.04% of compressed air volume, so minuscule quantities) are released from their bond with porous CMS – regeneration is therefore essentially the process where remaining air is vented to atmosphere then fresh compressed air can enter the columns and the whole process starts again – this is one PSA cycle.

If you have any any further questions please just let us know. You can do this by submitting another comment or by visiting

Kind regards,
Asad Raza Naeem - 06/06/2018 07:33

We are looking for a suitable generator to meet 125 Sm3/hr flow of N2 gas at 6 barg by the downstream process.

Simultaneously, it’s our process requirement to maintain a minimum pressure of 8 barg in our main N2 storage tank every time. This is because we need to have a back time of 30 minutes from our application in case of any power failure.

Our main N2 storage vessel volume is 16,000L.

Please advise accordingly.

bmcbride - 06/06/2018 08:45
Dear Mr Asad Raza Naeem,

Thank you for your enquiry, a member of our sales team will be in touch with you shortly to discuss your requirements in more detail and to provide a quote.

In future you can use our Request a Quote page at to request a quote directly through our customer service system to ensure a speedy response.

Kind regards,
Guna - 29/06/2018 14:12
We looking for as below spec



-pressure swing type

-generate nitrogen from ambient air with 99% purity

-normal flow rate min 5 litre/min at 5 barg

-gas purity control system & touch screen interface

-200 liter buffer tank

-come with compressor with outlet pressure min 7 barg

-come with condensed water removal

-particle filtration less than 0.01um

-piping & connection of stainless steel

-max dimension 70 x 75 x 200cm WXLXH

-pressure comply PED 2014/68/EU

Inclusive installation,testing & commissioning in Johore, Malaysia
Contact ±60167730434
bmcbride - 02/07/2018 10:11
Hi Guna,

Thank you for contacting Peak Scientific. I have passed your enquiry on to your local peak Scientific Sales team who will be in touch with you soon. For any future quote requests you can fill in our quote request form at to ensure you receive the quickest response possible.

Thank you for your enquiry.

Kind regards,
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