Experimental design of a "Snap-on" and standalone single-bed oxygen concentrator for medical applications

A novel single-bed, "Snap-on" and standalone, medical oxygen concentrator design based on a rapid pressure swing adsorption process was investigated for continuous oxygen supply. The Snap-on concentrator design is easy to hook up to an existing compressed air source, and the unit can then be readily used to produce oxygen for medical applications. It is easily transportable and compared to a traditional oxygen concentrator with its dedicated compressor, the Snap-on concentrator is particularly relevant for the oxygen therapy needs of a larger number of patients in situations such as COVID-19. A commercially available LiLSX zeolite was used for the separation of oxygen from compressed ambient air. The experiments were performed at different feed air pressures using a constant supply of house air in the lab. Further, the device performance was also analyzed using a standalone medium size air compressor. The minimum bed size factor obtained with compressed house air was 100 lb/tons per day contained (TPDc) O₂ at a cycle time of 7 s, whereas the minimum bed size factor obtained with a medium size air compressor weighing about 12 lbs was 210 lb/TPD_c O₂ at a cycle time of 14.5 s under the same feed pressures of 3.1 bar at an oxygen product purity of 90%. The product oxygen flow rate was nearly double for the same amount of adsorbent when using house air for the Snap-on design. The primary reason for this significantly higher oxygen production was the substantially higher and stable air throughput capacity of a typical house air compressor that enabled rapid cycling of the process at near-constant feed pressure compared to a medium size compressor used in a medical oxygen concentrator. The oxygen recovery was approximately 34% for both cases. Thus, the Snap-on oxygen concentrator was found to be easier to build and it delivered more oxygen for medical use compared to standalone units in locations where a constant supply of compressed feed air is available. This is typically the case in facilities such as hospitals, military medical camps and cruise ships. Further, the Snap-on design offers other benefits such as ease of transportation, higher reliability and lower weight.