Technologies for Oxygen, Nitrogen, and Argon

Atmospheric Gases Are Produced Using a Process Known as Air Separation


Cryogenic air separation is capable of producing large quantities of high purity gas and/or liquid phase product, which is then easily stored or used.

Non-cryogenic air separation is conducted near ambient temperature, so the product - oxygen or nitrogen - is always gas phase. Production quantity and purity in non-cryogenic air separation are not as high as the quantity and purity attainable with cryogenic air separation.



Cryogenic Air Separation

Large Scale Cryogenic Air Separation Units (ASUs) address the highest rate of demand for Oxygen, Nitrogen, and/or Argon.

Cryogenic ASUs produce large amounts of high purity oxygen, nitrogen, and argon by separating the air around us. Cryogenic ASUs can produce 100 to over 5,000 tons per day (TPD) oxygen. The reliability of cryogenic ASU technology is very high, often exceeding 99%.

Cryogenic air separation can be fairly energy intensive, consuming electricity (or other fuel) to achieve and maintain the temperatures required for the process. The process is something of a balancing act, with higher output purity coming at the cost of higher energy consumption. Conversely, the process can be "tuned" to operate at higher energy efficiency, albeit at a detriment to output purity.

air separation plants can be built onsite or used for pipeline delivery


MATHESON, together with parent company Nippon Sanso Holdings Corporation (NSHD), offers over 75 years of globally-recognized leadership in ASU design, fabrication, and operation.

The heart of an ASU is the “cold box” tower where the separation takes place. The MATHESON/TNSC cold box design and engineering are recognized for technical leadership and energy efficiency. Of course, a well-designed ASU is more than just a cold box. In addition to the ASUs we’ve built for our own use, we’ve built over 100 large scale ASUs in 10 countries over the last decade.

Cryogenic ASUs can be built onsite, with liquid phase product stored in cryogenic storage vessels. Cryogenic ASUs can be used to deliver gas phase product onsite or by pipeline.

MATHESON also operates a network of ASUs and a fleet of tanker trucks for production and delivery of liquid phase product to cryogenic storage vessels at your site.


Cryogenic vs. Non-Cryogenic Air Separation

Generally, cryogenic air separation is used for larger volume requirements. Oxygen or nitrogen produced by a cryogenic ASU is also more pure than the product of a non-cryogenic ASU. Oxygen purity can exceed 99.5%; nitrogen purity can exceed 99.99%.

Non-cryogenic air separation methods require less capital investment, operate in a smaller footprint, and are less complex. However, non-cryogenic methods typically are not practical above 500 TPD.

comparing cryogenic air separation with non-cryogenic air separation

Cryogenic ASUs become cost effective (versus non-cryogenic ASUs) at the level of about 200-300 tons per day (TPD) oxygen; and are most efficient above 500 to over 2,000 TPD. They are also more reliable.



Non-Cryogenic Air Separation

Non-cryogenic air separation is suited for low-to-moderate demand for nitrogen or oxygen. non cryogenic air separation system

While cryogenic air separation relies on the differences in boiling points of atmospheric gases, non-cryogenic air separation processes use physical property differences such as molecular size and mass. Non-cryogenic air separation is performed at near-ambient temperature and pressure.

The output product is gas phase, and would require liquefaction to be stored or transported in liquid phase.

The technologies used for non-cryogenic air separation – Pressure Swing Adsorption (PSA, oxygen or nitrogen), Vacuum-Pressure Swing Adsorption (VPSA, oxygen), and Membrane Separation (nitrogen) – lend themselves to faster (and lower cost) construction, a more compact installation footprint, and rapid startup. However, these non-cryogenic technologies require more post-separation purification compared to cryogenic ASUs, particularly for oxygen, which may contain close to 5% argon.



Interested in starting a dialogue about air separation for Oxygen, Nitrogen, or Argon production?

Contact the Refining/Engineering Experts directly.


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