Pressure Swing Adsorption Unit Research Articles

Multi-objective optimization of a hybrid carbon capture plant combining a Vacuum Pressure Swing Adsorption (VPSA) process with a Carbon Purification unit (CPU)

The imperative challenge posed by climate change requires urgent actions to counteract the harmful effects of greenhouse gas emissions, particularly CO2, which contributes to approximately 80 % of emissions responsible for global warming. A hybrid system combining Vacuum Pressure Swing Adsorption (VPSA) unit with a Cryogenic Carbon Purification Unit (CPU) is evaluated to enhance recovery and purity of CO2captured from flue gas containing CO2concentration ranging from 5 % to 20 %. VPSA preconcentrates the CO2and CPU completes the separation and purifies the CO2. The study uses surrogate models for multi-objective optimization, considering energy consumption, cost, and CO2recovery, providing a time-efficient approach for investigating computationally demanding processes. Results from the study indicate that the hybrid system achieves over 90 % recovery for flue gas concentration range considered, while ensuring the production of high-purity CO2(>99.99 %) suitable for transportation. A trade-off analysis reveals the balance between recovery, electricity consumption, and economic viability. A sensitivity analysis identifies parameters influencing recovery and energy consumption, providing guidance for future optimization efforts. The techno-economic analysis highlights the impact of electricity prices and carbon taxes on total costs, identifying an optimum towards higher recovery values under rising carbon taxes. Furthermore, the research underscores concentration-dependent economic feasibility, emphasizing the attractiveness of concentrations above 10 % compared with other technologies, which require higher concentrations. For an electricity price of 75 €.MWh−1, the total cost of the CO2 capture hydride system considering CO2 emissions with carbon tax of 100 €.tCO2−1 for concentrations ranging from 10 % to 20 % is from 123 to 80 €.tCO2−1, respectively. The analysis of the electricity source shows the importance of a low-carbon emission energy mix for optimal carbon emission reduction.

Simulation of Olive Pomace Gasification for Hydrogen Production Using Aspen Plus: Case Study Lebanon

Biomass is a renewable energy source gaining attention for its potential to replace fossil fuels. Biomass gasification can produce hydrogen-rich gas, offering an environmentally friendly fuel for power generation, transportation, and industry. Hydrogen is a promising energy carrier due to its high energy density, low greenhouse gas emissions, and versatility. This study aims to develop a hydrogen generation plant using a dual fluidized bed gasifier, which employs steam as a gasifying agent, to convert olive pomace waste from the Lebanese olive oil industry into hydrogen. The process is simulated using Aspen Plus and Fortran coding, and it includes a drying unit, gasification unit, gas cleaning unit, steam methane reformer unit, water–gas shift reactor unit, and a pressure swing adsorption unit. The generated gas composition is verified against previous research. Sensitivity analyses are conducted to investigate the impacts of the steam-to-biomass ratio (STBR) and gasification temperature on gas composition, demonstrating a valid STBR range of 0.5 to 1 and a reasonable gasification temperature range of 700 °C to 800 °C. Further sensitivity analyses assess the impact of reformer temperature and the steam-to-carbon ratio (S/C) on the gas composition leaving the steam methane reformer.

Optimization of hydrogen purification from biomass‐derived syngas via water gas shift reaction integrated with vacuum pressure swing adsorption for energy storage

AbstractBiomass is one of the promising sources to produce green H2, which can be considered an energy storage medium. To produce high‐purity H2 from biomass‐derived syngas, this study implemented a two‐stage H2 purification process. In the first stage, a water gas shift reaction (WGSR) was performed to enhance the H2 concentration in the syngas. The Taguchi method was employed to analyze the influence of the operating conditions and maximize the H2 concentration in the water gas shift reaction product. The results suggested that reaction temperature is a more dominant factor for enhancing the H2 concentration than the molar steam/carbon monoxide (S/CO) ratio. In the second stage, vacuum pressure swing adsorption was employed to obtain the high‐concentration H2 using the product from the water gas shift reaction having the optimum H2 concentration. Using the adsorption pressure as the primary parameter, it was found that high H2 purity and recovery could be obtained from vacuum pressure swing adsorption operated at low adsorption pressures. Based on this study's results, the vacuum pressure swing adsorption unit's best outcome occurs during an adsorption pressure of 2 kg·cm−2 and a flow rate of 17 L·min−1. Under these conditions, 93.61% H2 purity, 31.63% H2 recovery, 4.86 mol H2·(kgads·h)−1 productivity, and 448.14 kJ·(kg H2)−1 energy consumption are obtained.

Optimizing [formula omitted] capture in pressure swing adsorption units: A deep neural network approach with optimality evaluation and operating maps for decision-making

This study presents a methodology for surrogate optimization of cyclic adsorption processes, focusing on enhancing pressure swing adsorption units for carbon dioxide (CO2) capture. We developed and implemented a multiple-input, single-output (MISO) framework comprising two deep neural network (DNN) models, predicting key process performance indicators. These models were then integrated into an optimization framework, leveraging particle swarm optimization (PSO) and statistical analysis to generate a comprehensive Pareto front representation. This approach delineated feasible operational regions (FORs) and highlighted the spectrum of optimal decision-making scenarios. A key aspect of our methodology was the evaluation of optimization effectiveness. This was accomplished by testing decision variables derived from the Pareto front against a phenomenological model, affirming the surrogate model’s reliability. Subsequently, the study delved into analyzing the feasible operational domains of these decision variables. A detailed correlation map was constructed to elucidate the interplay between these variables, thereby uncovering the most impactful factors influencing process behavior. The study offers a practical, insightful operational map that aids operators in pinpointing the optimal process location and prioritizing specific operational goals.

Hydrogen safety effect calculation (dispersion and thermal radiation effects) for determination of siting and safe distance

AbstractThe main aim of this study was to evaluate the potential effect of dispersion, thermal radiation, and explosion from a poly‐bed pressure swing adsorption (PSA) unit with its surrounding facility to determine its safety distance. Thus, the Shell FRED (fire, release, explosion, and dispersion) consequence modeling was used to predict the impact of a release scenario and assist in designing, developing, and maintaining safe operation. This study was intended to calculate dispersion contours to 50% lower flammable limit (LFL) and 100% LFL, thermal impacts of radiation flux levels of 4, 5, 12.5, and 37.5 kW/m2 at a distance, and including explosive effects of 0.1, 0.2, and 0.35 bar to the chosen target. Based on the findings, it was found that, to avoid exposure to heat radiation of 12.5 kW/m2 from the PSA unit, equipment should be located at a minimum distance of 20.84 m. Meanwhile, process modules and buildings must be located at a minimum distance of 13.8 m. The explosive nature of hydrogen makes on‐site handling and storage more challenging than fossil fuels. The findings of this study will have important implications for the future handling and storage of hydrogen as a potential fuel.

Integration of large-scale pressure swing adsorption units in local hospitals in Morocco: Design, simulation and performance evaluation

To enhance the availability and accessibility of medical oxygen in local hospitals in Morocco, a solid approach has been conducted for upscaling PSA unit. This comprehensive research involves the design, simulation, and performance evaluation of the PSA unit to confirm the functioning and efficiency of the system. The design phase meticulously considers hospital oxygen requirements, utilizing data from multiple local hospitals. Objectives include using PSA technology to produce high-purity oxygen, providing autonomy for 30–35 patients at 5 L/min. Although, the hospital needs 650 L/min of medical oxygen in order to supply all the patients. The study reveals promising results for oxygen concentration which reaches a maximum of 96 % of oxygen under 29 mol/min of flowrate which give an equivalent to 660 L/min volumetric flow rate that can supply the needs of local hospitals within a short time. These findings will enable hospitals decision makers to consider large PSA over cryogenic separation unit that has been known with major drawbacks in delivery and pose logistical and environmental problems and to ensure a steady and reliable supply of medical oxygen, ultimately contributing to improved healthcare services and patient care.

Development of a hybridized small modular reactor and solar-based energy system for useful commodities required for sustainable cities

The current study develops a hybridized small modular nuclear reactor and solar-based system designed specifically for sustainable communities in metropolitan areas to meet their power, heat, clean fuel, fresh water and food requirements. Both floating-type and bifacial-type photovoltaic arrays are integrated with a high-temperature gas-cooled small modular reactor. In the integrated system, a Rankine cycle subsystem for power generation, a solid oxide electrolyzer for hydrogen production, a pressure swing adsorption unit with ammonia reactor for nitrogen and then ammonia production, a multi-effect desalination unit for freshwater generation, and heat recovery units in order to provide heating to residential area, food drying facility, greenhouse, and fish farm facilities. For both floating and bifacial PV options, the 120 MWp PV modules are considered and integrated with two small modular reactor units at 250 MWth capacities each, 500 MWth in total. A thermodynamic analysis, which is based on energy and exergy approaches, is carried out. The time-dependent analyses are carried out for floating-type PV and bifacial-type PV options for the cities of Istanbul in Turkey; Barcelona in Spain; Los Angeles (LA) in the United States; Tokyo in Japan; and Toronto in Canada by using their hourly meteorological data, source and load capacities in a typical meteorological year. Among ten cases, between 112835 and 146180 tonnes of ammonia are generated in a typical year while meeting the heating and power requirements of sustainable communities in metropolitan areas. Among ten cases, the average overall energy and exergy efficiencies are found as 41.04% and 46.88%, respectively. The hybridization of such nuclear and solar systems achieves unique advantages by preventing intermittencies compared to the renewable-alone systems, reducing carbon emissions compared to fossil-based systems, and lowering the levelized costs of energy compared to the nuclear energy-alone systems.

Adaptive digital twin for pressure swing adsorption systems: Integrating a novel feedback tracking system, online learning and uncertainty assessment for enhanced performance

This paper presents a novel approach to digitizing and modeling pressure swing adsorption (PSA) processes using an uncertainty-aware digital twin. PSA modeling presents unique challenges due to its complex and cyclic behavior, which lacks a steady state. By contributing to the literature on periodic systems, we provide valuable insights into the potential applications of artificial intelligence and digital twins beyond the field of cyclic processes. Our proposed methodology can enhance the understanding and optimization of complex systems across various industries and applications. The proposed digital twin is uncertainty-aware and reliable, continuously updating itself through online learning and utilizing a novel feedback tracker to accurately represent the PSA system. This robust and adaptable methodology supports optimal PSA system operation and facilitates informed decision-making for enhanced process operation. The results demonstrate that the proposed approach yields a reliable digital twin for the PSA unit, capable of tracking the process’s complex dynamics and adapting to changes, including adsorbent degradation, which is a significant challenge in PSA operations. Overall, this work highlights the potential of advanced technologies, such as digital twins and artificial intelligence, to improve performance and efficiency in the field of process engineering. This work contributes to the ongoing efforts to optimize industrial processes and support sustainable development by providing a reliable and adaptable methodology for digitizing PSA processes.

Simulation And Optimization Of Hydrogen Production By Steam Reforming Of Natural Gas

Hydrogen (H2) production through natural gas steam reforming is widely adopted due to its cost-effectiveness and energy efficiency. A simulation and optimization study was performed on an industrial natural gas steam reforming system using Aspen Hysys V12 software to optimize this process. The study focused on optimizing various parameters, including the Reformer Reactor, Water Gas Shift Reactor, and purification units such as the Separator and Pressure Swing Adsorption (PSA). The Reformer and Water Gas Shift reactors were set at 900 °C and 300 °C, respectively, to maximize hydrogen production. Under specific conditions of 5 atm pressure and a steam-to-carbon ratio (S/C) of 2.5, the process achieved a hydrogen production rate of 402.2 kg/h. The treatment zone effectively eliminated ~ 100% of undesirable CO2 and CO gases, with only trace amounts of CH4 and H2 remaining in the waste gases. Additionally, the PSA unit efficiently removed ~ 100% of the water from the separator, ensuring water-free dry gases were sent to the PSA unit. The integration of heating and cooling heat exchange units reduced energy consumption by approximately 51.6%. After the removal of undesired gases in our PSA unit, the production yield for the final product (H2, based on dry gas inlet to PSA) is 77.83%, resulting in 100% pure dry H2. In the waste gas outlet (tail gas) of PSA a composition (22.17%), includes CO, CO, H2O, and CH4. Resulting high-quality hydrogen is well-suited for a wide range of applications, including fuel cells, petroleum refining, natural gas refineries, and petrochemical processes.

Process-based evaluation of adsorbents: effect of CMS pellet size on N2-PSA performance

AbstractThe process-based evaluation of adsorbents is considered the most foolproof method with respect to a particular application, as it provides data about the separation effectiveness in authentic operating conditions. This paper presents empirically obtained performance results of the kinetically-controlled air separation on multiple carbon molecular sieves carried out in a twin-bed pressure swing adsorption unit. The effect of adsorbent pellet size on nitrogen productivity and air demand is studied at different product purity levels (10–10,000 ppm O2 of the residual oxygen concentration), operating temperatures (25–45 °C), and half-cycle times (35–70 s). The selected process conditions correspond to the majority of practical applications. Guidelines for the suitable particle size depending on the desired nitrogen purity are given.

Small-scale medical oxygen production unit using PSA technology: modeling and sensitivity analysis

This study presents a solid approach for small-scale medical oxygen production unit using pressure swing adsorption (PSA) technology. The objective of this research is to develop a mathematical model and conduct a sensitivity analysis to optimise the design and operating parameters of the PSA system. Based on the simulation results, an optimal set of operational parameter values has been obtained for the PSA beds. The result shows that the binary system produced oxygen with a purity of 94%, at the adsorption pressure 1 bar and temperature of 308K. The findings demonstrate the effectiveness of the proposed small-scale PSA system for medical oxygen production, highlighting the impact of key parameters and emphasising the need for careful optimisation. The findings serve as a guide for the design and operation of small-scale PSA systems, enabling healthcare facilities to produce their own medical oxygen, thereby improving accessibility and addressing critical shortages during emergencies. Future research may explore the integration of large scale PSA units in hospitals in Morocco.

Optimal design of pressure swing adsorption units for hydrogen recovery under uncertainty

Abstract The paper proposes an approach to the optimal design of pressure swing adsorption (PSA) units for hydrogen recovery under uncertainty, which provides a reasonable margin of the potential resource of the PSA hydrogen unit and compensates for the negative impact of a random change in uncertain parameters within specified limits. A heuristic iterative algorithm is proposed to solve the design problem with a profit criterion, which is guaranteed to provide the technological requirements for the PSA unit, regardless of the values that take uncertain parameters from the specified intervals of their possible change. An experimental verification of the approach with the root-mean-square error of 19.43 % has been carried out. Optimization problems of searching for a combination of mode and design parameters under uncertainty for a range of 4-bed 4-step VPSA units with a capacity of 100–2000 L/min STP have been solved taking into account the requirements for hydrogen purity of 99.99+ %, gas inlet velocity of 0.2 m/s, and bed pressure drop (no more than 1 atm). It has been established that taking into account uncertainties leads to an increase in energy costs by 8–10 %, a decrease in profit by 10–15 %, and a decrease in hydrogen recovery by 4–5 %, which is a payment for the uninterrupted operation of the PSA unit. The effect of uncertain parameters (percentage composition of the gas mixture; gas temperature; the diameter of adsorbent particles) on the key indicators of the PSA process (recovery, profit, hydrogen purity, unit capacity) has been established and trends in adsorption duration, adsorption and desorption pressure, P/F ratio, valve capacity, bed length, adsorber diameter for design of hydrogen PSA unit, which are necessary for subsequent design and scaling of units.

Scale-up analysis of a twin-bed PSA pilot plant

Small-scale pressure swing adsorption (PSA) plants, also referred to as pilot plants, are commonly exploited for studying separation processes in favour of the development of mathematical models and scale-up strategies. The applicability of a lately presented mathematical model, which was developed based on experimental data acquired from a high-purity twin-bed N2-PSA pilot plant, is verified in this paper for the design of large-scale systems by an analysis of the mass transfer zone development at different PSA cycle times. Effects of the PSA scale-up factor, adsorber aspect ratio, packed-bed density, and flow resistances along the piping system on the process performance are studied numerically. These considerations are particularly relevant for the scale-up of bank-type PSA units as well as for skid-mounted systems fitted to local space limitations, where the standard scale-up concept of keeping the gas velocity constant often cannot be fully realised. It is demonstrated that the sensitivity of the PSA performance to studied factors increases along with the required product purity level. Therefore, recommendations for adequate dimensions of pilot plants depending on the desired gas purity level can be derived. Limitations of the gas velocity through the adsorber shall be observed to generate reliable simulation data. The agreement between experimental results obtained from an industrial-scale system on one hand, and the outcome of a dynamic simulation on the other hand, is confirmed—provided that realistic pressure profiles are generated by a proper adjustment of flow resistances along the piping.

Process Simulations of High-Purity and Renewable Clean H2 Production by Sorption Enhanced Steam Reforming of Biogas

Renewable clean H2 has a very promising potential for the decarbonization of energy systems. Sorption enhanced steam reforming (SESR) is a novel process that combines the steam reforming reaction and the simultaneous CO2 removal by a solid sorbent, such as CaO, which significantly enhances hydrogen generation, enabling high-purity H2 production. The CO2 sorption reaction (carbonation) is exothermic, but the sorbent regeneration by calcination is highly endothermic, which requires extra energy. Biogas is one of the available carbon-neutral renewable H2 production sources. It can be especially relevant for the energy integration of the SESR process since, due to the exothermic sorption reaction, the CO2 contained in the biogas provides extra heat to the system, which can help to balance the energy requirements of the process. This work studies different process configurations for the energy integration of the SESR process of biogas for high-purity renewable H2 production: (1) SESR with sorbent regeneration using a portion of the produced H2 (SESR+REG_H2), (2) SESR with sorbent regeneration using biogas (SESR+REG_BG), and (3) SESR with sorbent regeneration using biogas and adding a pressure swing adsorption (PSA) unit for hydrogen purification (SESR+REG_BG+PSA). When using biogas as fuel (Cases 2 and 3), these configurations were studied using air and oxy-fuel combustion atmospheres in the sorbent regeneration step, resulting in five case studies. A thermodynamic approach for process modeling can provide the optimal process operating conditions and configurations that maximize the energy efficiency of the process, which are the basis for subsequent optimization of the process at the practical level needed to scale up this technology. For this purpose, process simulations were performed using a steady-state plant model developed in Aspen Plus, incorporating a complex heat exchanger network (HEN) to optimize heat integration. A comprehensive parametric study assessed the effects of biogas composition, temperature, pressure, and steam to methane (S/CH4) ratio on the process performance represented by the selected key performance indicators, i.e., H2 purity, H2 yield, CH4 conversion, cold gas efficiency (CGE), net efficiency (NE), fuel consumption for the sorbent regeneration step, and CO2 capture efficiency. H2 with a purity of 98.5 vol % and a CGE of 75.7% with zero carbon emissions can be achieved. When adding a PSA unit, nearly 100% H2 purity and CO2 capture efficiency were achieved with a CGE of 77.3%. The use of oxy-fuel combustion during regeneration lowered the net efficiency of the process by 2.3% points (since it requires an air separation unit) but allowed the process to achieve negative carbon emissions.

Process design and optimization of onsite hydrogen production from ammonia: Reactor design, energy saving and NOX control

Ammonia is an important commodity for both direct and indirect applications. It can be used directly as a carbon-free fuel source as well as for the purpose of renewable hydrogen storage and transport. In this study, hydrogen production from ammonia decomposition in a multi catalytic packed bed reactor with an intermediate heating system is reported using Aspen Plus V.12. The process simulation model results have been validated through experimental data for commercially available Ru/Al2O3 catalyst and Temkin-Phyzev reaction kinetics. The results exhibit that ammonia decomposition is a highly endothermic reaction, therefore requires significant heat energy. The decomposition parameters such as temperature and pressure are optimized for large-scale ammonia decomposition. For the ammonia combustion, thermal efficiency, fuel-saving, and product yield are analyzed and optimum values are found to be 59%, 22% and 77% for each parameter, respectively. During the pure ammonia combustion, NOX emissions are a major issue. To monitor the NOX emissions, parameters such as equivalence ratio, temperature and pressure are analyzed to witness the optimum operating conditions. To improve the flame quality such as laminar velocity, minimum ignition temperature, and adiabatic flame temperature of the ammonia combustion, waste hydrogen stream from the pressure swing adsorption (PSA) unit is blended with the fuel ammonia. The blending of hydrogen with fuel ammonia resulted in higher NOX emissions, which can be reduced by recirculation of 30% of the flue gas with air–fuel stream.

Techno-economic analysis of plastic wastes-based polygeneration processes

To address the plastic waste reduction and reutilization, three designs of mixed plastic wastes-based polygeneration processes are named Designs 1–3. Designs 1 and 2 produce MeOH and electricity simultaneously by using the cryogenic air separation unit (CASU) and the vacuum pressure swing adsorption unit (VPSA), respectively. To increase the capacity of capturing CO2, the calcium looping process (CaLP) is involved in Design 3 to produce the products of H2 and CO2 and recover waste heat for power generation. The complicated CaLP dramatically increases the total costs of Design 3, although the carbon capture ratio of Design 3 is superior to other designs. If the cumulative carbon revenue is counted into the total annual income according to the emission trading scheme, the economic evaluation shows that Design 3 has a higher net present value (NPV), or a higher internal rate of return (IRR), or a shorter dynamic payback period (DPP) than other designs.

Biogas upgrading by pressure swing adsorption using zeolite 4A. Effect of purge on process performance

The use of bio-methane as a fuel is an important alternative to reduce the emission of greenhouse gases. Pressure swing adsorption (PSA) processes using carbon molecular sieve adsorbents are industrial state-of-the-art technologies for biogas upgrading. Replacing the CMS adsorbent with a cheaper alternative can be a way to reduce costs for downscaling the technology to make it available to farms operating at low flows and avoiding large methane emissions to atmosphere.We have evaluated the use of zeolite 4A as a selective material that partially excludes (or strongly delays) CH4 adsorption. Adsorption equilibrium and kinetics (at zero-coverage) of pure gases (283, 303 and 323 K) was measured. Adsorption equilibrium was fitted with the multi-site Langmuir model and there is a difference of 3 orders of magnitude in diffusion constants. Binary breakthrough and a two-column PSA experiment were performed to validate a mathematical model. The model was used to determine good operating conditions with this adsorbent material. Bio-methane purity over 98 % was obtained at a recovery biome-thane of ∼ 90 %. These performance indicators were obtained in similar pressure conditions as commercial adsorbents used in industrial PSA units indicating that zeolite 4A is a viable alternative for biogas upgrading processes.

Handling model uncertainty in control of a pressure swing adsorption unit for syngas purification: A multi-model zone control scheme-based robust model predictive control strategy

The application of a robustly stabilizing model predictive control (MPC) strategy to a pressure swing adsorption (PSA) unit, hitherto unexplored in the literature, is addressed in this work. Here, a set of linear models to handle model uncertainties describes the PSA nonlinear dynamic behaviour. Each model represents a different operating condition of the PSA, generating a multi-model uncertainty description. In addition to incorporating the multi-model uncertainty, the proposed MPC control law deals with a controlled output zone tracking scheme to systematically accommodate typical cyclic steady states of a PSA process. From the industrial standpoint, economic targets on process variables (controlled outputs, manipulated inputs, or both) are also incorporated into the robust control method. A Real-Time Optimizer usually defines these targets, making up a two-layer control scheme. The effectiveness of the robust MPC is evaluated in a syngas purification process via a single bed, six-step PSA unit composed of a porous amino-functionalized titanium terephthalate MIL-125-type MOF adsorbent.

Carbon-negative hydrogen from biomass using gas switching integrated gasification: Techno-economic assessment

Ambitious decarbonization pathways to limit the global temperature rise to well below 2 °C will require large-scale CO2 removal from the atmosphere. One promising avenue for achieving this goal is hydrogen production from biomass with CO2 capture. The present study investigates the techno-economic prospects of a novel biomass-to-hydrogen process configuration based on the gas switching integrated gasification (GSIG) concept. GSIG applies the gas switching combustion principle to indirectly combust off-gas fuel from the pressure swing adsorption unit in tubular reactors integrated into the gasifier to improve efficiency and CO2 capture. In this study, these efficiency gains facilitated a 5% reduction in the levelized cost of hydrogen (LCOH) relative to conventional O2-blown fluidized bed gasification with pre-combustion CO2 capture, even though the larger and more complex gasifier cancelled out the capital cost savings from avoiding the air separation and CO2 capture units. The economic assessment also demonstrated that advanced gas treatment using a tar cracker instead of a direct water wash can further reduce the LCOH by 12% and that the CO2 prices in excess of 100 €/ton, consistent with ambitious decarbonization pathways, will make this negative-emission technology economically highly attractive. Based on these results, further research into the GSIG concept to facilitate more efficient utilization of limited biomass resources can be recommended.

The Potential of Oxygen -Pressure Swing Adsorption Unit Connected with Electricity Storage System

The Potential of Oxygen -Pressure Swing Adsorption Unit Connected with Electricity Storage System