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Non-cryogenic Air Separation

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Gas processing or air separation is a very old technology of science involving the separation of air and the identification of oxygen as an atmospheric component. Such a process owes its origin with the origin of chemistry. There are basically two basic technologies of air separation: Cryogenic air separation and Non cryogenic air separation.

While the cryogenic technique is a traditional method, the non-cryogenic air separation is however a very new technology. Non cryogenic air separation was developed during the 1970s. While cryogenic gas separation requires large sized plants for its processing, the non cryogenic process is considered to be a convenient, efficient, and economical method to buying gas in high pressure cylinders or for purchasing bulk liquid products to be vaporized. This process is preferable for many small scale users of oxygen or nitrogen.

What exactly is Non Cryogenic Separation?
The traditional method of producing nitrogen and oxygen gases is cryogenic air separation which involves the process of cooling air in large sized plants to several hundred degrees below zero in order to separate the component gases. Non-cryogenic air separation is however a very new technology that requires air to force through through special materials that selectively pass or retain the oxygen or nitrogen. The physical properties of the gases other than the temperature like molecular size and mass are exploited in non cryogenic air separation process to produce discrete and refine elements of air at close-to-atmospheric temperature. Operating at near-ambient temperature, these are then used to produce commercially valuable gaseous products like oxygen and nitrogen.

There are three main technologies involved in non cryogenic process. They are

Pressure Swing Adsorption (PSA) used in nitrogen and oxygen generators
Vacuum-Pressure Swing Adsorption (VPSA) used in oxygen generators and
Membrane Separation, used to produce nitrogen gas.

We will discuss in details the three processes in the section:

Types of non-cryogenic air separation

Advantages of Non Cryogenic Separation Processes

The non cryogenic technique is much smaller in size than cryogenic plants
The basic advantage is that it can be placed directly on the customer's site
They are efficient and economical choices when demand is relatively small and when very high product purity is not required
They are compact
They can operate at near-ambient temperature and pressure
Once installed, they can be brought on-line in less than 30 minutes.

Conclusion
Non cryogenic gas processing is growing up in recent years though it has not been able to completely displace other existing technologies. The process is gradually gaining market share in those applications where it has a clear economic or technical advantage. Both technology-push and market-pull factors have contributed to the running of non separation process centered on PSA, VPSA or membrane technology. For many manufacturers and suppliers, these non-cryogenic gas separations must play against the long established cryogenic separations involved in bulk gas business.

Non-cryogenic gas processes are on the way to altering the economics of certain processes and expanding the markets, applications, and uses of gases. The separation of air into oxygen, nitrogen, natural gas purification, hydrogen recovery will become increasingly important across a wide spectrum of very specific applications. Using non-cryogenic separations all types of gas streams can be processed. According to recent report, the present and future markets for non-cryogenic gas separations include the following:

Air Separation --nitrogen and oxygen enriched air
Natural Gas Clean up
Hydrocarbon Clean-up
Hydrogen Separations
Hydrogen recovery from off-gases
Miscellaneous --rare gases, drying

Tags:- Non Cryogenic Air Separation, Non Cryogenic Separation Processes

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