10th August 2018
How Do PSA Nitrogen Generators Work? - Pressure Swing Adsorption
The gas separation process in (Pressure Swing Adsorption) PSA nitrogen generators is based on the ability to fix various gas mixture components and particles by a physical solid substance. These are called adsorbents.
Adsorption in psa nitrogen generators
The gas separation process in PSA nitrogen generators is based on the ability to fix various gas mixture components and particles by a physical solid substance. These are called adsorbents.
PSA process illustration
PSA nitrogen generators
The technology of air-to-nitrogen generation with the use of adsorption processes in PSA nitrogen generators is well studied and widely applied at industrial facilities for the recovery of high-purity nitrogen. This is then used in many industries from food packaging to supporting laboratory instrumentation such as Liquid Chromatography Mass Spectrometry (LC-MS) and Gas Chromatography (GC).
PSA nitrogen generators for these scientific applications are designed to produce high purity nitrogen by regulating gas adsorption and adsorbent regeneration by changing pressures in two adsorber-adsorbent containing vessels. This process requires a constant temperature, close to ambient.
The swing adsorption process in each of the two adsorbers consists of two stages running at intervals of a few minutes. At the adsorption stage oxygen, moisture and carbon dioxide molecules diffuse into the pore structure of the adsorbent whilst the nitrogen molecules are allowed to travel through the adsorber–adsorbent-containing vessel to be delivered as high purity nitrogen to the application.
Advantages of PSA nitrogen generators
Quality of nitrogen gas
Nitrogen generators allow for the production of high purity nitrogen from the surrounding atmosphere, which can provide – up to 99.9995% nitrogen depending on the nitrogen generator system.
Reliability of nitrogen generator
Nitrogen generators allow for continuous operation 24/7, giving you an uninterrupted flow of gas when it's needed.
Flexibility of nitrogen gas supply
The application of the nitrogen gas can be diverse and altered at short notice. So long as the nitrogen generator can meet the flow and purity requirements of the application it can be changed from one day to the next with minimal hassle.
Low cost of ownership
By substituting out-of-date cylinder technology, on-site nitrogen production savings largely exceed 50% for a typical LC-MS application. The net cost of nitrogen produced by nitrogen generators is significantly less than the cost of bottled or liquefied nitrogen.
Long lasting nitrogen supply
On-site generators are highly resistant to vibration and shocks, chemically inert to greases and moisture insensitive. With proper, planned, in most cases annual, maintenance a generator can easily last a decade or more.
Disadvantages of PSA nitrogen generators
A gas generator purchase can be a significant initial purchase. However, labs can quickly recoup the initial cost through savings of alternative supplies of gas (such as nitrogen cylinders) in less than 12 months.
Purity is directly related to flow rate. High purity-high flow rate nitrogen generators are more expensive, nevertheless the solution will still be cheaper in the long run when compared with bulk gas supply.
A PSA nitrogen generator provides a more cost effective nitrogen supply for analytical laboratories than traditional cylinder gas or bulk supply methods. Ongoing costs of ordering cylinders and time spent reordering cylinders and changing over old cylinders is no longer required.