Search Results (55)

The large-scale production of high-purity hydrogen via pressure swing adsorption (PSA) remains a prominent research focus. This study develops a multi-component heat and mass transfer model for a lean hydrogen mixture (N₂/CO₂/H₂/CO = 44.6/35.4/19.9/0.1 mol%) on a coal-derived activated carbon (AC)/zeolite 13X layered bed to investigate its breakthrough curve and PSA purification performance. The model is implemented on the Aspen Adsorption platform and validated with published data. Parametric analysis of the breakthrough curve reveals that a high pressure and a low feed flow rate can delay the breakthrough of impurity gases. The simulated variations in pressure, purity, and recovery during the PSA cycle align with the published results. Studies on PSA cycle parameters show that, in general, a high pressure, a low feed flow rate, a short adsorption time, and a high P/F ratio improve purity but reduce recovery. The purity and recovery of the layered bed outperform those of the single-layer bed. Specifically, gradually modifying the AC/zeolite 13X length ratio from 10:0 to 5:5 enhances hydrogen purity, while adjusting it from 10:0 to 3:7 enhances hydrogen recovery. At AC/zeolite 13X = 5:5, the highest purity was 97.38%, while at AC/zeolite 13X = 3:7, the highest recovery was 49.13%. Full article

The conceptual design and techno-economic assessment of Pressure Swing Adsorption (PSA) for the recovery of H₂, CO₂, and CO from steel making Blast Furnace-Basic Oxygen Furnace and Coke Oven off-gases, major contributors to anthropogenic carbon emissions, are presented. Three PSA units are modeled on Aspen Adsorption V14, each utilising dedicated adsorbents and configurations tailored for the target gas. Model validation is successfully conducted by comparing breakthrough simulation results with experimental data. The simulation results demonstrate that the PSA systems effectively separate H₂ (99.3% purity, 80% recovery), CO (98% purity, 87% recovery), and CO₂ (96.9% purity, 75% recovery) from steelmaking off-gases. Meanwhile, the techno-economic assessment indicates that the PSA systems are economically viable, with competitive costs of £2768/tH₂, £52.78/tCO, and £16.89/tCO₂ captured, making them an effective solution for gas separation in the steel industry. Full article

Biohydrogen has been identified as an attractive renewable energy carrier due to its high energy density and green production from biomass and organic wastes. Efficient biohydrogen production is a challenge that demands precise control of process parameters. Regulation and optimization of biohydrogen production through advanced approaches are therefore necessary to improve its industrial viability. This study introduces an innovative proposal for controlling the Pressure Swing Adsorption (PSA) process by employing a neural network-based controller derived from a PID control framework. The neural network was trained using input–output data, enabling it to maintain biohydrogen production purity at approximately 99%. The proposed neural network effectively simulates the dynamics of the PSA model, which is traditionally controlled using a PID controller. The results demonstrate exceptional performance and strong robustness against disturbances. Specifically, the neural network enables precise tracking of the desired trajectory and effective attenuation of disturbances, achieving a biohydrogen purity level with a molar fraction of 0.99. Full article

Hydrogen (H₂) is a key energy carrier and industrial feedstock, with growing interest in its production from syngas and water–gas shift (WGS) syngas. Effective purification methods are essential to ensure high hydrogen purity for various applications, particularly fuel cells, chemical synthesis, or automotive fuel. Pressure swing adsorption (PSA) has emerged as a dominant separation technology due to its efficiency, scalability, and industrial maturity. This study reviews PSA-based hydrogen purification and proposes an experimental framework based on literature insights. Key process variables influencing PSA performance, such as adsorbent selection, cycle sequences, pressure conditions, and flow configurations, are identified. The proposed experimental methodology includes breakthrough adsorption studies and PSA process evaluations under dynamic conditions, with variations in column configuration, adsorption pressure (8–9 bar), and process concept (Berlin and Linde Gas). The purpose of the review is to prepare for syngas separation by the selected process in terms of hydrogen recovery and purity using ITPE’s advanced technological facilities. The findings are expected to contribute to improving PSA-based hydrogen purification strategies, offering a pathway for enhanced industrial-scale hydrogen production. This work provides a foundation for bridging theoretical PSA principles with practical implementation, supporting the growing demand for clean hydrogen in sustainable energy systems. Full article

Metal–organic frameworks (MOFs) based on the pressure swing adsorption (PSA) process show great promise in separating argon from air. As research burgeons, the number of MOFs has grown exponentially, rendering the experimental identification of materials with significant gas separation potential impractical. This study introduced a high-throughput screening through a two-step strategy based on structure–property relationships, which leveraged Grand Canonical Monte Carlo (GCMC) simulations, to swiftly and precisely identify high-performance MOF adsorbents capable of separating argon from air among a vast array of MOFs. Compared to traditional approaches for material development and screening, this method significantly reduced both experimental and computational resource requirements. This research pre-screened 12,020 experimental MOFs from a computationally ready experimental MOF (CoRE MOF) database down to 7328 and then selected 4083 promising candidates through structure–performance correlation. These MOFs underwent GCMC simulation assessments, showing superior adsorption performance to traditional molecular sieves. In addition, an in-depth discussion was conducted on the structural characteristics and metal atoms among the best-performing MOFs, as well as the effects of temperature, pressure, and real gas conditions on their adsorption properties. This work provides a new direction for synthesizing next-generation MOFs for efficient argon separation in labs, contributing to energy conservation and consumption reduction in the production of high-purity argon gas. Full article

As the global shift toward a low-carbon economy accelerates, hydrogen is emerging as a crucial energy source. Among conventional methods for hydrogen production, steam methane reforming (SMR), commonly paired with pressure swing adsorption (PSA) for hydrogen purification, stands out due to its established infrastructure and technological maturity. This comprehensive techno-economic analysis focuses on membrane-based hydrogen production, evaluating four configurations, namely SMR, SMR with PSA, SMR with a palladium membrane, and SMR with a ceramic–carbonate membrane coupled with a carbon capture system (CCS). The life cycle cost (LCC) of each configuration was assessed by analyzing key factors, including production rate, hydrogen pricing, equipment costs, and maintenance expenses. Sensitivity analysis was also conducted to identify major cost drivers influencing the LCC, providing insights into the economic and operational feasibility of each configuration. The analysis reveals that SMR with PSA has the lowest LCC and is significantly more cost-efficient than configurations involving the palladium and ceramic–carbonate membranes. SMR with a ceramic–carbonate membrane coupled with CCS also demonstrates the most sensitive to energy variations due to its extensive infrastructure and energy requirement. Sensitivity analysis confirms that SMR with PSA consistently provides the greatest cost efficiency under varying conditions. These findings underscore the critical balance between cost efficiency and environmental considerations in adopting membrane-based hydrogen production technologies. Full article

Hydrogen purity plays a crucial role in the expanding hydrogen economy, particularly in applications such as fuel cells and industrial processes. This review investigates the relationship between hydrogen production methods and resulting purity levels, emphasizing the differences between reforming, electrolysis, and biomass-based techniques. Furthermore, it explores state-of-the-art purification technologies, including pressure swing adsorption (PSA), membrane separation, and cryogenic distillation, highlighting their effectiveness and limitations in achieving ultra-pure hydrogen. Analytical methods such as gas chromatography, mass spectrometry, and cavity ring-down spectroscopy are also discussed in terms of their accuracy and application scope for hydrogen quality assessment. By integrating findings from global and domestic studies, this paper aims to provide a comprehensive understanding of the challenges and advancements in hydrogen purity, offering insights into optimizing hydrogen for a sustainable energy future. Full article

The simultaneous optimization of complex process units and hydrogen networks is a significant challenge in refinery hydrogen network integration. To address this, an evolutionary response surface-based collaborative optimization method is proposed, enabling the concurrent optimization of pressure swing adsorption (PSA) and the hydrogen network. This method develops a mechanistic model for PSA and alternates between random sampling and evolutionary response surface-based hydrogen network optimization to obtain diverse sampling points and potential optimal solutions. The PSA mechanistic model is then used to compute the accurate output parameters for the sampled points, and these parameters are incorporated into the hydrogen network optimization to obtain precise objective function values. An efficient optimization framework is presented to streamline the process. The proposed method is applied to a refinery hydrogen network integration case study, comprehensively considering both PSA costs and hydrogen utility costs. The results demonstrate that the method is computationally efficient and effectively reduces the refinery’s total annual costs. The accuracy of the optimization results is significantly improved compared to traditional methods, providing an effective solution for the collaborative optimization of the refinery hydrogen network and PSA. Full article

Pressure swing adsorption (PSA) technology is among the most efficient techniques for purifying and separating hydrogen. A layered adsorption bed composed of activated carbon and zeolite 5A for a gas mixture (H₂: 56.4 mol%, CH₄: 26.6 mol%, CO: 8.4 mol%, N₂: 5.5 mol%, CO₂: 3.1 mol%) PSA model was built. The simulation model was validated using breakthrough curves. Then, a six-step PSA cycle model was built, and the purification performance was studied. The Box–Behnken design (BBD) method was utilized in Design Expert software (version 10) to optimize the PSA purification performance. The independent optimization parameters included the adsorption time, the pressure equalization time, and the feed flow rate. Quadratic regression models can be derived to represent the responses of purity and productivity. To explore a better optimization solution, a novel optimization method using machine learning with a back propagation neural network (BPNN) was then proposed, and a kind of heuristic algorithm–genetic algorithm (GA) was introduced to enhance the architecture of the BPNN. The predicted outputs of hydrogen production using two kinds of models based on the BPNN–GA and the BBD method integrated with the BPNN–GA (BBD–BPNN–GA). The findings revealed that the BBD–BPNN–GA model exhibited a mean square error (MSE) of 0.0005, with its R–value correlation coefficient being much closer to 1, while the BPNN–GA model exhibited an MSE of 0.0035. This suggests that the BBD–BPNN–GA model has a better performance, as evidenced by the lower MSE and higher correlation coefficient compared to the BPNN–GA model. Full article

Hydrogen, a vital resource, is utilized in many process units within the refinery. The purification system is widely used to regenerate and improve hydrogen quality, therefore reducing fresh hydrogen consumption. Pressure swing adsorption (PSA) and membrane separation (MS) technologies are widely utilized for the purification of hydrogen, and the process can be optimized by constructing mathematical models. Thus, at first, a parametric analysis of the purification models is conducted to identify the key variables of these models during the optimization process, which also reveals the necessity of coupling multiple purification units. Then, a superstructure-based hydrogen network (HN) model comprising multi-stage PSA and MS units is constructed, aiming to determine the optimal hydrogen allocation and purification system. This model considers the simultaneous optimization of purification system parameters, including operating pressure, in conjunction with its structural configuration. This case study demonstrates the applicability of the HN model to diverse refinery scenarios. Additionally, compared to using a single purification unit, using a multi-unit purification system can improve purification efficiency and reduce the total cost by 2% to 22%. Full article

Metal–organic frameworks (MOFs) are promising materials for processes such as carbon dioxide (CO₂) capture or its storage. In this work, the adsorption of CO₂ and nitrogen (N₂) in Co₃(ndc)₃(dabco) MOF (ndc: 2,6-naphthalenedicarboxylate; dabco: 1,4-diazabicyclo[2.2.2]octane) is reported for the first time over the temperature range of 273–323 K and up to 35 bar. The adsorption isotherms are successfully described using the Langmuir isotherm model. The heats of adsorption for CO₂ and N₂, determined through the Clausius–Clapeyron equation, are 20–27 kJ/mol and 10–11 kJ/mol, respectively. The impact of using pressure and/or temperature swings on the CO₂ working capacity is evaluated. If a flue gas with 15% CO₂ is fed at 6 bar and 303 K and regenerated at 1 bar and 373 K, 1.58 moles of CO₂ can be captured per kg of MOF. The analysis of the multicomponent adsorption of typical flue gas streams (15% CO₂ balanced with N₂), using the ideal adsorbed solution theory (IAST), shows that at 1 bar and 303 K, the CO₂/N₂ selectivity is 11.5. In summary, this work reports essential data for the design of adsorption-based processes for CO₂ capture using a Co₃(ndc)₃(dabco) MOF, such as pressure swing adsorption (PSA). Full article

In oxygen production on plateaus, pressure swing adsorption (PSA) oxygen production is currently the most commonly used oxygen production method. In plateau regions, low pressure leads to a decrease in adsorbent nitrogen–oxygen separation performance, which affects the performance of PSA oxygen production, so it is particularly important to enhance adsorbent nitrogen–oxygen separation performance. In this paper, Li-LSX (lithium low-silicon aluminum X zeolite molecular sieve) adsorbents were modified using the liquid phase ion exchange method, and five kinds of modified adsorbents were obtained, namely AgLi-LSX, CaLi-LSX, ZnLi-LSX, CuLi-LSX, and FeLi-LSX, respectively. The influences of different metal ions and modification time lengths on the adsorbent nitrogen adsorption and nitrogen–oxygen separation coefficients were analyzed. Through theoretical calculations, the nitrogen and oxygen adsorption and separation performances of the modified adsorbents at different altitudes and low adsorption pressures were investigated. It is shown that the nitrogen adsorption capacity of the AgLi-LSX-1 adsorbent obtained from the modification experiment reaches 27.92 mL/g, which is 3.24 mL/g higher than that of Li-LSX; the nitrogen–oxygen separation coefficients of S1 and S2 are 19.24 and 7.54 higher, respectively; and the nitrogen–oxygen separation coefficients of S4 are 20.85 and 7.54 higher than those of Li-LSX, respectively. With the increase in altitude from 50 m to 5000 m, the nitrogen–oxygen separation coefficient of the AgLi-LSX-1 adsorbent increased rapidly from 20.85 to 57, and its nitrogen–oxygen separation coefficient S4 exceeded that of the Li-LSX adsorbent to reach 47.61 at an altitude of 4000 m. Therefore, the modified adsorbent AgLi-LSX-1 in this paper can enhance the performance of the PSA oxygen process for oxygen production in plateau applications. Full article

The paper presents a case study that applies a model predictive control (MPC) approach in a Micro850 programmable logic controller (PLC) to a laboratory pressure swing adsorption (PSA) process used for separating gas mixtures of CO₂ and CH₄. PLC is an industrial hardware characterized by its robustness to hazardous environments and limited computational capacities, which poses computational challenges for MPC implementation. This paper’s main contribution is the application of the modified Takagi–Sugeno–Kang-based MPC (MTSK-MPC) algorithm to this PSA unit, which provides features to investigate and implement feasible MPC designs in PLCs. The investigation consists of a sensitivity analysis of how some design parameters influence the PLC memory and the MPC implementation and a comparative evaluation of the computational processing from different MPC algorithms and simulations. The comparison comprises software-in-the-loop simulations with three algorithms in the PC: an implicit MPC, an explicit MPC, and the MTSK-MPC. Additionally, it includes a hardware-in-the-loop simulation with the implemented MTSK-MPC in Micro850. The results show that the MPC algorithms achieve close performance, tracking setpoint changes and rejecting output disturbances, with the MTSK-MPC presenting the lower processing time among the MPCs in the PC. The study concludes that the implementation of MTSK-MPC in the Micro850 is feasible. Full article

This publication explores current and prospective methods for hydrogen production and purification, with a strong emphasis on membrane-based technologies for purification and separation. This focus is justified by the ongoing shift towards renewable energy sources (RESs) in electricity generation, necessitating strategic changes to increase hydrogen utilization, particularly in the automotive, heavy road, and rail sectors, by 2025–2030. The adoption of hydrogen from RESs in the construction, energy, and industrial sectors (e.g., for process heat or fertilizer production) is also under consideration, driving the need for innovative production, separation, and purification methods. Historically, industrial-scale hydrogen has been predominantly derived from fossil fuels, but renewable sources such as electrolysis, biological, and thermal processes now offer alternatives with varying production efficiencies (0.06–80%) and gas compositions. Therefore, selecting appropriate separation and purification methods is critical based on specific usage requirements and the gas composition. Industrial-scale hydrogen purification commonly employs pressure swing adsorption (PSA) technologies, capable of achieving up to 99.99% purity. Cryogenic distillation is suitable for applications needing up to 95% purity. Membrane technologies, including polymer, metallic, and electrolytic membranes, have traditionally been limited to moderate volumes of pure gas production but are crucial for hydrogen purification and separation. This publication critically evaluates the potential of membrane technology for hydrogen separation, particularly in response to the anticipated rise in demand for RES-derived hydrogen, including from renewable feedstocks. Full article

Hydrogen is an industrial raw material both for the production of chemicals and for oil refining with hydrotreating. It is the subject of increasing attention for its possible use as an energy carrier and as a flexible energy storage medium. Its production is generally accomplished in Steam Methane Reforming (SMR) plants, where a gaseous mixture of CO and H₂, with a limited number of other species, is obtained. The process of production and purification generates relevant amounts of carbon dioxide, which needs to be removed due to downstream process requirements or to limit its emissions to the atmosphere. A work by IEAGHG focused on the study of a state-of-the-art Steam Methane Reforming plant producing 100 kNm³/h of H₂ and considered chemical absorption with MethylDiEthanolAmine (MDEA) solvent for removing carbon dioxide from the PSA tail gas in a baseline scheme composed of the absorber, one flash vessel and the regeneration column. This type of process is characterized by high energy consumption, in particular at the reboiler of the regeneration column, usually operated by employing steam, and modifications to the baseline scheme can allow for a reduction of the operating costs, though with an increase in the complexity of the plant. This work analyses three configurations of the treatment section of the off gas obtained after the purification of the hydrogen stream in the Pressure Swing Adsorption unit with the aim of selecting the one which minimizes the overall costs so as to further enhance Carbon Capture and Storage in non-power industries as well. Full article