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

Abstract

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) O 2 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 O 2 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.

Highlighting the Anti-Synergy between Adsorption and Diffusion in Cation-Exchanged Faujasite Zeolites

“…The N 2 /O 2 diffusion selectivities for Na-FAU are only slightly higher than those of Li-FAU (see Figure b). The CBMC/MD data rationalize the use of LiX, with Al ≈ 96 uc –1 , in the industrial practice. , …”

“…The CBMC/MD data rationalize the use of LiX, with Al ≈ 96 uc –1 , in the industrial practice. 29 , 30 …”

“…Li + cation-exchanged FAU (faujasite) zeolite is commercially used for separation of N 2 /O 2 mixtures. ,, For supplying medical grade oxygen to prevent hypoxemia-related complications related to COVID-19, portable medical oxygen concentrators commonly use LiLSX (LS = low silica; Si/Al ≈ 1) to achieve high N 2 /O 2 adsorption selectivities, ensuring enhanced rejection of purified O 2 , the desired product. , …”

“…23,27,28 For supplying medical grade oxygen to prevent hypoxemia-related complications related to COVID-19, portable medical oxygen concentrators commonly use LiLSX (LS = low silica; Si/Al ≈ 1) to achieve high N 2 /O 2 adsorption selectivities, ensuring enhanced rejection of purified O 2 , the desired product. 29,30 For separation applications using pressure-swing adsorption (PSA) technology, consisting of adsorption/desorption cycles, there is often a mismatch between the requirements of strong adsorption and ease of desorption. 31 For example, NaX has a very strong affinity for CO 2 , but the regeneration requires application of deep vacuum.…”

Cutting Oxygen Production-Related Greenhouse Gas Emissions by Improved Compression Heat Management in a Cryogenic Air Separation Unit

“…Strained oxygen supplies remain critical nowadays, especially in India and Africa [25][26][27]. Alternative methods of medicinal oxygen production have been tested successfully [28]; however, many hospitals and healthcare facilities rely on a high-percentage oxygen supply from large cryogenic air separation units (ASU). While its supply is in the spotlight of the media, its carbon footprint has received far less attention [29].…”