How Does PSA Work? It’s All About the Swing!

Oxygen is essential for supporting life as well as many other industrial and environmental applications. This makes it one of the largest selling chemicals on the planet.

Oxygen exists in the atmosphere around us. It makes up approximately 21% of the air we breathe. If only that oxygen could be separated......

The technology behind all of our standard oxygen generators is the Pressure Swing Adsorption (PSA) process. It is the engine that drives the separation of oxygen from air. It is a purely physical process; there are no chemical, electrical, or other reactions in our process.

For certain specific applications, we can make a variation of the PSA process, called the Vacuum Pressure Swing Adsorption (VSA/VPSA) process. The only differences are that VPSA uses a feed blower instead of an air compressor and the absorber vessels are desorbed through a vacuum blower. The net result is a significant decrease in the power consumption of the system as a whole. However, these plants are typically only cost effective for very large oxygen capacities.

Air contains 21% oxygen, 78% nitrogen, 0.9% argon, and 0.1% other gases. Oxygen Generating Systems separate oxygen from compressed air through a unique Pressure Swing Adsorption (PSA) process. The PSA process uses molecular sieve (synthetic zeolite), which attracts (adsorbs) nitrogen from air at high pressure and releases (desorbs) it at low pressure. Oxygen Generators use two vessels filled with molecular sieve as adsorbers. As compressed feed air flows through one of the vessels, the molecular sieve adsorbs nitrogen.

The Pressure Swing Adsorption process for the generation of enriched oxygen gas from ambient air utilises the ability of a synthetic Zeolite Molecular Sieve to absorb mainly nitrogen. While nitrogen concentrates in the pore system of the Zeolite, Oxygen Gas is allowed to pass through as a product.

As Compressed Air passes up through one of the Adsorbers, the molecular sieve selectively adsorbs the Nitrogen. This then allows the remaining Oxygen to pass on up through the adsorber and exit as a product gas.

When the adsorber becomes saturated with Nitrogen the inlet airflow is switched to the second off line adsorber. The first adsorber is regenerated by desorbing nitrogen through De-Pressurisation and purging it with some of the product oxygen. The cycle is then repeated and the pressure is continually swinging between a higher level at adsorption (Production), and a lower level at desorption (Regeneration).