Nitrogen with Pressure Swing Adsorption

In PSA technology a specific gas species is separated from a mixture of gases under high pressure and at ambient temperature by passing the pressurized air through an adsorbent. Separation of gases is based on their different affinity for the adsorbent. At high pressure more gas is adsorbed, and when the pressure is reduced the gas is again released.

The adsorbents we use are ZMS and CMS for oxygen and nitrogen, respectively. Under normal operation conditions these molecular sieves are subject to practically no wear, and thus have minimal servicing requirements. The straightforward design and and construction of the units guarantee their reliability.

Please see more detailed info on nitrogen and oxygen production with PSA technology here.

Nitrogen PSA process can be described with following steps.

1. Compression, drying and filtering of input air: 

The ambient air is compressed by an air compressor. Before entering the PSA process the compressed air is dried and filtered. 

2. Oxygen adsorption on CMS bed: 

Our PSA units have two cylinders filled with Carbon Molecular Sieve. (CMS). Compressed and purified air is conducted to one of these cylinders. As the air flows through the cylinder, the (CMS) bed adsorbs oxygen and trace gases, while nitrogen passes through to the nitrogen accumulation tank. The adsorption process is interrupted before the CMS becomes saturated with oxygen and trace gases by diverting the input air to the second cylinder, which at this point starts producing nitrogen.

3. Oxygen desorption and CMS bed regeneration: 

The CMS of the first cylinder (now saturated with oxygen) is regenerated by reducing pressure in the cylinder below that of the adsorption step. The adsorbed oxygen is released and vented into atmosphere. After this step it is again ready for another cycle.

4. Nitrogen accumulation in receiver tank: 

Adsorption and desorption steps are repeated in the CMS tanks at equal time intervals. A constant flow of nitrogen is conducted to nitrogen receiver tank, which can store the nitrogen to pressures up to 7-8 bar.

5. Nitrogen pressurization: 

From the accumulation tank nitrogen can either be fed to in house gas network or bottled in cylinders. With our compressors pressures up to 900 bar can be reached. 

The maximum nitrogen purities reached with our systems are 99,9999 %. The standard systems cover flowrates from 4 l/min to 1000 l/min. Even higher flowrates can be customized according to customer`s needs. The outlet nitrogen pressures can be tailored up to 900 bar.

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