The use of high quality medical grade oxygen became commoditized with the advent of compact oxygen concentrators (also known as oxygen generators). The pressure swing principle (PSA) is used in these portable devices to transfer atmospheric air into a molecular sieve adsorbent, concentrating oxygen in the process. Portable oxygen concentrators are ideal for home-based health care, improving indoor air quality, and other non-industrial applications.Since most commonly available oxygen concentrators follow a common operating concept, selecting the right adsorbent is crucial for maximising oxygen generation. We'll help you choose the right molecular sieve for use in portable oxygen concentrators in this short article.
Molecular sieve, a synthetic zeolite with superior adsorptive properties, has been used in a variety of desiccant technologies in the pharmaceutical and food industries. Furthermore, molecular sieve binds nitrogen, separating it from oxygen in the air, and it is because of this property that it has become the preferred adsorbent for portable oxygen concentrators. To separate high-purity medical grade oxygen from ambient air, most portable oxygen concentrators use either the pressure swing adsorption (PSA) or vacuum pressure swing adsorption (VPSA) mechanisms. This is accomplished by blowing air into a molecular sieve cartridge contained within the concentrator. Nitrogen is absorbed by the molecular sieve as the air pressure in the concentrator changes, allowing high-purity oxygen to migrate through the flowthrough. The filtered oxygen (93.3% purity) is then pumped into an outlet for use in health treatment or other situations as required.
Nitrogen's high affinity and reversible binding to molecular sieve allow for the creation of long-lasting, self-cleaning compact oxygen generators. When the oxygen concentrator is turned on, it concentrates oxygen using one molecular sieve cartridge. A portion of the filtered oxygen is then fed into a secondary molecular sieve cartridge to remove any nitrogen molecules that have been stuck. This was achieved in expectation of the primary cartridge's binding quality deteriorating over time. The oxygen generator feeds air through the secondary cartridge to concentrate oxygen while still back-fed the first cartridge to extract bound nitrogen from the molecular sieve matrix until the first cartridge is saturated.
Although sodium-based zeolites are widely used in pharmaceutical applications, studies have shown that ion-exchanged lithium-based molecular sieve outperforms sodium-based 13X and 5A molecular sieve in terms of oxygen recovery. From a technical point of view, the zeolite has a much closer relationship with the quadrupole moment of each nitrogen molecule moving through the cartridge as the Na+ cation in a sodium-based molecular sieve is replaced with the Li+ cation. For portable concentrators using lithium-based molecular sieve cartridges, this leads to high performance, high purity (93 percent 3% ) oxygen recovery at ambient temperature.
The nitrogen/oxygen selectivity of lithium-based molecular sieve is nearly three times that of sodium-based molecular sieve, and the ability for static nitrogen adsorption is nearly three times that of sodium-based molecular sieve. Lithium-based molecular sieves have a higher product gas potential than sodium-based molecular sieves, making them a safer alternative for producing high-purity compressed oxygen for emergency medical treatment. Oxygen concentrators can now be assembled with a very limited footprint thanks to the use of lithium-based molecular sieves, making them suitable for the often space-constrained home-based care climate.
