Pressure Swing Adsorption Oxygen Research Articles

Molecular insights into improved oxygen adsorption: Ag+ and Ce3+ doping in Li-LSX for air separation

Pressure swing adsorption (PSA) is a cost-effective and efficient method for oxygen production. It is crucial to improve the adsorption capacity of zeolite adsorbent material to facilitate oxygen production for PSA. Based on the molecular simulation method, the Ag+ and Ce3+ were doped into Lithium-based Low Silica X (Li-LSX) zeolite to enhance the adsorption of O2. The developed adsorption model is in good agreement with the experimental results. Equilibrium parameters including adsorption capacity, heterogeneity, and N2/O2 selectivity were obtained by fitting with the Langmuir-Freundlich model. The results showed that the N2/O2 selectivity of AgLi-LSX with a 30% Ag+ exchange ratio was 3.2% higher compared with Li-LSX, while the adsorption capacity of CeLi-LSX with a 30% Ce3+ exchange ratio was 27.4% greater for O2 than Li-LSX. In addition, the isosteric adsorption heats and distributions of potential energy were simulated to reveal the mechanism of performance enhancement. The adsorption capacity for O2 exhibited a sustained increase trend as the exchange ratio of Ce3+ increased. The findings of this research can guide the development of oxygen-selective adsorbents and reduce the cost of PSA oxygen production.

Research on Air Filter Monitoring System of Oxygen Generator

Zeolite is an expensive consumable material in oxygen generator which needs to be replaced regularly. The life of zeolite is mainly determined by dust, humidity and temperature. Among which, dust has a great influence on the life span of zeolite. In the process of oxygen production, the dust in the air will be adhered to the molecular sieve, and shorten the life of zeolite. PSA (Pressure Swing Adsorption) oxygen generator has a filter at the air inlet end, which is used to filter out the dust particles in the air. The filters of PSA oxygen generator are disposable regularly. The replacement cycle depends on the air environment, and the cycle is short if under much dust particles.This thesis investigates the architecture of the filter failure detection. The architecture can detect the air environment dust condition, detect the filter failure, prolong the life of the filter.

Application of Molecular Sieve Oxygen Generation Mini-plant under Harsh Environment

Pressure Swing Adsorption (PSA) oxygen generation mini-plant is widely used in all various hospitals for its fast, convenient, and cost-effective features. However, considering the landscape of global markets, the PSA medical oxygen generation mini-plant design basis varies from location to location. Therefore, it forces the manufacturer to design and build the PSA oxygen generation mini-plant more flexibly to enable its compatibility in different extreme ambient conditions (temperature, humidity, pressure, cleanliness) of installation location. For the sake of these concerns, this paper employs the concept of modularity as an approach to PSA medical-grade oxygen generation mini-plant design and application and elaborates 10 key components for 4 modules of PSA medical-grade oxygen generation mini-plant, namely (a) air compressor module; (b) PSA module; (c) oxygen compressor module; (d) smart control module. Under this modularized design approach, this paper investigates the technical features and the design criticality of modular and key components in fulfilling the expected performance, finally achieving and maintaining the overall performance of PSA oxygen generation mini-plant with the selected modules which may be installed worldwide. This paper helps to highlight the variability of PSA oxygen generation mini-plants in harsh environments in four dimensions (temperature, humidity, pressure, cleanliness) and briefs the methodology of the phase gate model for modular approach in oxygen generation mini-plant. It contributes to the literature on this important subject in the modularized design method, adsorption technology, air separation process, etc.

Second wave of COVID-19 pandemic and the surge of mucormycosis: Lessons learnt and future preparedness: Indian Society of Anaesthesiologists (ISA National) Advisory and Position Statement.

Second wave of COVID-19 pandemic and the surge of mucormycosis: Lessons learnt and future preparedness: Indian Society of Anaesthesiologists (ISA National) Advisory and Position Statement.

Two-Dimensional Modeling of Pressure Swing Adsorption (PSA) Oxygen Generation with Radial-Flow Adsorber

Radial flow is an important type of flow direction for large-scale pressure swing adsorption (PSA) oxygen generation systems. In this study, a numerical simulation of a PSA oxygen generation process based on radial-flow adsorbers was performed with two-dimensional CFD modeling. The gas distribution, the maldistribution factor and the pressure difference were comparatively investigated at each flow type of the radial-flow adsorber. Considering the gas adsorption performance, the results indicated that the centripetal π-flow radial adsorber has the best flow characteristics for the PSA process. The oxygen purity distribution within the adsorption bed was studied to compare centripetal and centrifugal π-flows, and the former was shown to perform better on oxygen enrichment and adsorbent desorption. The steady state was achieved after eight cycles for the centripetal-π adsorber and each of the four steps of the PSA process was explored in detail to show the advantageous properties for oxygen generation in terms of adsorption and desorption. The relationships between the product flow rate and the oxygen purity and recovery were further investigated.

Superoxygenation: analysis of oxygen transfer design parameters using high-purity oxygen and a pressurized column

There remains significant potential for improvement in oxygen transfer efficiency, which can account for 60% of water and wastewater treatment energy requirements. This research examined superoxygenation, or aerating water under pressure with high-purity oxygen gas. Examined were the effects superoxygenation has on five key aeration design parameters: the mass transfer coefficient (KLa), saturation concentration ([Formula: see text]), standard oxygen transfer rate (SOTR), standard aeration efficiency (SAE), and standard oxygen transfer efficiency (SOTE). This research compared values under pressures of 0, 50, 100, 150, and 200 kPa using air and pressure swing adsorption (PSA) generated oxygen. It was found that with increasing pressure for both air and PSA oxygen: KLa decreased, [Formula: see text] increased, SOTR and SAE remained constant, and SOTE increased. While comparing air and PSA oxygen, oxygen was found to have a similar KLa, larger [Formula: see text], SOTR, and SOTE, and a lower SAE. It was concluded that superoxygenation is a viable method for increasing oxygen transfer and could potentially reduce oxygenation costs in water treatment processes.

Analysis of Design Factors Influencing the Oxygen Transfer of a Pilot-Scale Speece Cone Hypolimnetic Aerator

The objective of this research was to characterize the performance of a pilot scale downflow bubble contact (DBCA) hypolimnetic aerator, the Speece Cone. The effect of two key design factors, inlet water velocity and the ratio of gas flow rate to water flow rate on four standard units of oxygen transfer, was examined: (a) the oxygen transfer coefficient, KLa, corrected to 20°C, KLa20 (h−1); (b) the standard oxygen transfer rate, SOTR (g O2·h−1); (c) the standard aeration efficiency, SAE (g O2·kW h−1); and (d) the standard oxygen transfer efficiency, SOTE (%). Two sources of oxygen, pressure swing adsorption (PSA) oxygen (87% purity oxygen) and air (∼21% oxyzen) were compared. KLa20, SOTR, and SAE increased with an increase in the ratio of gas flow rate to water flow rate for both air and oxygen, over a range of 0.5% to 5.0%; while SOTE deceased. An increase in inlet water velocity resulted in a decrease in KLa, corrected to 20°C, SOTR, and SAE, but an increase in the SOTE. Experimental treatments with air showed similar, but much less dramatic effect of the gas flow rate to water flow rate ratio and water inlet velocity on KLa20, SOTE, SAE, and SOTE, when compared to treatments with PSA oxygen. The best oxygen transfer performance was achieved with an inlet water velocity of 6.9–7.6 m·s−1 and oxygen flow rate to water flow rate ratio of about 2.5%. At this combination, the SOTE was about 66–72%. Further experimentation with inlet water velocity is required to increase oxygen transfer performance to the >95% range which has been reported in the literature for Speece Cone oxygenation systems.

Decolorization of molasses by a new isolate of Geotrichum candidum in a jar fermenter

Decolorization of crude molasses by a newly isolated dye-decolorizing fungus, Geotrichum candidum Dec 1, was conducted in a jar fermentor system having fan-type propellers and a pressure swing adsorption oxygen generator. The oxygen-fortified air supply was effective not only to obtain a highest decolorization degree of 80% molasses but also the highest peroxidase activity which is responsible for the decolorization of the dyes. © Rapid Science Ltd. 1998