Pressure Swing Research Articles

Novel side-reactor dividing wall column and reactive distillation process for enhanced electronic-grade propylene glycol monomethyl ether acetate production

The semiconductor industry is experiencing rapid growth and has become one of the largest sectors in the world. Propylene glycol monomethyl ether acetate (PGMEA) is prized for its exceptional properties and its ability to meet the stringent requirements as a solvent for electronic processing. This work aims to enhance the production of electronic-grade PGMEA through a practical and advanced intensified configuration. First, the kinetic reactor for propylene glycol monomethyl ether (PGME) synthesis has been modeled and pinpointed optimal operating conditions through sensitivity analysis. Subsequently, several process alternatives incorporating intensified techniques, such as the dividing wall column (DWC), pressure swing distillation (PSD), reactive DWC (RDWC), and side-reactor DWC (SR-DWC), have been investigated. These processes have been systematically designed and optimized through a sequential design procedure. Response surface methodology, a practical optimization method, has been employed to optimize the complex column's structure with the help of Aspen Plus and Minitab. Energy requirements and costs of all process alternatives were evaluated for a fair comparison. The SR-DWC-RD process has emerged as the most promising option, as it can save up to 11.5 % in energy requirements and 19.9 % in total annual costs. This practical design, complete with detailed optimal design parameters, presents significant opportunities for improving industrial PGMEA production.

Thermodynamic modeling and performance analysis of chemical looping gasification combined with steam reforming for municipal solid waste: An Aspen Plus approach

Chemical looping gasification combined with steam reforming (CLG-SR) holds great promise for improving energy efficiency and streamlining the production of renewable H2 and synthetic fuels. In this investigation, the process underwent simulation and analysis using Aspen Plus, offering valuable insights into product outcomes, environmental impacts, and economic performance. The accuracy of the model was validated against experimental results from the literature, yielding a root mean square (RMS) of 4.17 %, thereby demonstrating its high feasibility. The findings demonstrate that within the temperature range of 700–800 °C, H2 achieves notable selectivity, reaching 60.68 % selectivity at 700 °C. When the steam-to-municipal solid waste (MSW) ratio surpasses 0.9, H2 demonstrates elevated selectivity. Notably, it is crucial to observe that the selectivity of CO2 also escalates concurrently with that of H2. Specifically, at steam-to-MSW ratio (SMR) of 0.9, the selectivity of H2 attains 60.72 %, whereas the selectivity of CO2 attains 27.69 %. Under these parameter conditions, H2, purified through pressure swing adsorption (PSA), constitutes 68.59 % of the total input H elements, leading to an impressive energy efficiency of 47.76 %. The economic analysis, based on the model, discloses a material consumption of 7.40 tons per ton of H2, resulting in a total production cost of 2487.20 USD per ton of H2. The study bears paramount strategic significance for advancing the in-depth research and development of chemical looping gasification technology.

Oxygen generation and delivery: Start to end

Oxygen is vital for our life. In hospitals, the medical team should also have knowledge of its generation and how it ends till it is ready for consumption at the patient end. Various oxygen generation plants like pressure swing adsorption (PSA) plants, Liquid medical oxygen plant are available at every medical institute but basic technical knowledge holds importance. Medical gas pipeline system is a well designed network spread through out the hospitals which boost life in the patients but utmost handling and care of these necessitates regular check and audits to that every point of the system provides maximum usage with minimum leakage. (Provide appropriate messages of about 35-50 words to be printed in centre box): Oxygen is the very basis for survival of the patients. Careful planning and knowledge is the essential requirement. Why is it important is well known, but how and whats of the oxygen generation plants is the need of the hour.

Reactive distillation with inter-integrated vapor permeation for 1,3-Dioxolane production: Experiments, modeling, process analysis and design

To overcome the problem of difficult separation of the 1,3-dioxane (DOL)-H2O azeotrope in the production of DOL, a new high-integrated technology via reactive distillation (RD) with inter-integrated vapor permeation (VP) (abbreived as R-VP-D) was established. A series of R-VP-D experiments were conducted to find the effect of dedydration on reactant conversion and DOL content in the distillate. A two-dimensional VP module modeled by Aspen Custom Modeler (ACM) was combined with two RD modules in Aspen Plus to simulate the entire R-VP-D process, and the R-VP-D model was verified by experimental results. Then, by this model, systematic research on VP inserting position and membrane area on the reaction performance, reboiler and condenser duty, catalyst load, and TAC of the R-VP-D column was performed. The mechanism of how dehydration promotes reaction was explored. Finally, a new RD-VP-D technology for producing 99.9wt% DOL was designed and optimized. Two goals were achieved by inserting VP: obtaining a DOL-H2O mixture that crosses the azeotropic point in the distillate and improving reaction performance by removing by-product H2O. Under the optimal parameter, the energy consumption per unit product was reduced by 3.9% with less equipment, a simpler process, and less required land area compared with the RD with pressure swing distillation technology reported in the literature, and CO2 emissions were reduced by 4.0%. The reason why promotion effect is insignificant was explored, which is related to which of separation or reaction is the control step in RD process.

Efficient hybrid strategy for simultaneous design of refinery hydrogen networks and pressure swing adsorption unit

Refineries face increasing hydrogen demand due to the consumption of heavy and sour crude oil. This study presents a novel hybrid method to optimize hydrogen network configurations with a rigorous pressure swing adsorption (PSA) process model. This method utilizes Bayesian optimization to address the upper-level unknown constraints black-box optimization problem while employing deterministic algorithms to manage the lower-level nonlinear programming problem. Furthermore, infeasible regions are transformed into feasible ones by introducing a dummy stream, and the costs incurred during the transformation process are accurately calculated. The proposed method is validated using two literature cases. In Case 1, Bayesian optimization outperformed the Kriging model, resulting in a 7.84% reduction in total annual cost (TAC). In Case 2, a comparison of four search strategies revealed the developed two-phase strategy as the most effective one. This method offers a powerful and practical tool for optimizing real-world hydrogen networks with PSA processes.

Evaluation of an alternative process for the production of hydrocarbons from CO2: Techno-economic and environmental analysis

This study aims to evaluate and compare two integrated processes (Plant A and B) for hydrocarbon production from CO2. They involve proton exchange membrane water electrolysis for H2 production, reverse water-gas shift reaction for syngas production, pressure swing adsorption for syngas purification, Fischer-Tropsch synthesis for diesel-range hydrocarbons from CO2, and atmospheric distillation for product separation. Plant B additionally integrates a hydrocracking-based upgrading section. The simulations were performed using Aspen Plus® v10, Aspen Adsorption® v10, and Aspen Custom Modeler® v10. The evaluation covers technical, economic, environmental, and multi-criteria assessment (GREENSCOPE). The proposed processes demonstrate the potential to convert CO2 to hydrocarbons, with carbon conversion rates of 75% and 71% for Plants A and B, respectively. Process energy intensity is 155 and 170 MJ/kgLP for Plants A and B, respectively. Environmental assessment reveals CO2 reduction, resulting in negative global warming potentials of −2.20 and −0.84 kgCO2-eq/kgLP for Plants A and B, respectively. The sustainability degree indices for Plants A and B are 1.00 and 0.06, respectively, indicating Plant A as the more sustainable process alternative based on both quantitative and qualitative metrics. Economic analysis shows project unviability in the Brazilian context due to reliance on H2 production and prevailing pricing conditions. Economic viability requires a price increase of liquid products by 266% and 302% or CO2-eq abatement costs ranging from 2.05 to 3.43 US$/kgCO2-eq for Plants A and B, respectively. GREENSCOPE methodology indicates better performance for Plant A across all scores, highlighting a clear connection between the hydrocracking unit and performance indicators. The findings show that these processes align with sustainable development goals (SDGs) targets for climate action (SDG 13), clean energy (SDG 7), industry, innovation, and infrastructure (SDG 9), decent work and economic growth (SDG 8), and responsible consumption and production (SDG 12). Overall, the research moves forward SDGs by offering solutions to cut carbon emissions and promote sustainable industrial practices.

Pressure swing adsorption of Li exchange hierarchical X zeolite for pure hydrogen from binary gas mixture

This study reports the separation of pure hydrogen (H2) employing pressure swing adsorption (PSA). The Li-X and Li-hierarchical X (Li–H-X) zeolite were prepared by an ion exchange process. The sorbents were evaluated through several experiments including, breakthrough, empty bed contact time (EBCT), single-bed, and two-bed PSA with different steps. The effect of pressure, purity, and recovery relationship was developed. The high-pressure PSA study was performed at 4, 6, and 10 bar with varying feed flow rates to assess their efficacy in pure H2 separation using binary gas stream (H2/CO2, 75/25 vol.%). The breakthrough adsorption capacity of Li–H-X exhibited 3.4 mmol g−1 and 0.212 mmol g−1 of CO2 and H2, respectively. Li–H-X shows ∼8% higher CO2 sorption capacity than the Li-X sorbent at 1 bar and 300 K due to the large meso-microporous structure of the sorbent. The two-bed PSA purity and recovery were found higher than single-bed PSA. Using two-bed PSA, the Li–H-X achieved a 99.5% of purity, 92.9% of recovery, and 10.4 mL min−1 g−1 of productivity, which was ∼16% higher recovery and productivity than single-bed PSA at a flow rate of 1200 mL min−1 at 6 bar. With increasing the pressure and flow rate, the recovery of Li–H-X was enhanced up to 93.7% with 99.1%–99.9% H2 purity. The long-term PSA was run using Li–H-X sorbent for 7.5 h with 230 cycles with H2 purity between 98.5 and 99.5% at 6 bar. Interestingly, the adsorbent shows the scalability of PSA for efficient H2 separation for a binary mixture of H2/CO2.

A different strategy to reduce energy consumption for designing heterogeneous decanter-assisted advanced pressure-swing distillation process

In this work, we aim to explore the feasibility of integrating two strategies, i.e., (1) introducing a small quantity of solvent as a makeup stream and (2) employing a decanter, to develop an energy-efficient pressure swing distillation process for ternary azeotropic separation. The addition of a minor amount of solvent aims to facilitate the transition of the feed composition from outside the liquid–liquid equilibrium region to within it. This transition could enable the use of a decanter, thereby promoting a more energy-efficient separation process with reduced reliance on pressure-driven mechanisms. A systematic approach was proposed to explore this concept, involving the different thermodynamic features for conceptual design followed by process optimization and process evaluation. This approach was exemplified using a mixture containing chloroform, ethanol, and water. Two solvent and decanter-assisted triple-column pressure-swing azeotropic distillation (SD-TCPSAD) process were developed and evaluated against the conventional triple-column pressure swing distillation in terms of economic, energy, and environmental performance. Among the three configurations, SD-TCPSAD I exhibited the most favorable outcomes, achieving a 61 %, 69 %, and 69 % improvement in economic, energy, and environmental impact. These improvements were primarily attributed to the utilization of smaller column sizes, the utilization of different heating utilities, and a substantial decrease in overall energy consumption.

Active gas camera mass flow quantification (qOGI): Application in a biogas plant and comparison to state-of-the-art gas cams.

Gas cameras are primarily used to detect gas leaks, but their use has been increasingly extended to mass flow quantification (qOGI). We employ the previously published active illuminated gas camera [Bergau etal. "Real-time active-gas imaging of small gas leaks," J. Sens. Sens. Syst. 12, 61-68 (2023) and Bergau etal. "Flow rate quantification of small methane leaks using laser spectroscopy and deep learning," Process Saf. Environ. Prot. 182, 752-759 (2024)] in a real-world application for quantification, enhancing the camera with two new features: sensitivity adaptation and camera-gas distance detection. This technology was applied to a gas leak found in the pressure swing adsorption room of a biogas plant in Germany. We compare its performance with state-of-the-art quantification gas cameras (qOGI), such as Sensia Mileva 33. Such a comparison between active and passive gas cameras is possible for the first time due to the introduced sensitivity tuning. Additionally, we enclosed the gas leak and measure the methane concentration with a flame ionization detector, providing a gold standard for comparison. Our findings revealed relative offsets to our gold standard of -57% and +319% for the DAS-camera and the Sensia, respectively, suggesting that the accuracy of mass flow quantification could be improved through the use of active gas cameras.

Impacto de la oxigenoterapia a alto flujo a través de la insuflación de gas a alta velocidad sobre la fracción de engrosamiento diafragmático en sujetos sanos

ObjectiveThe primary objective of this study was to evaluate the impact of high-flow nasal cannula oxygen therapy [HFNC] on the diaphragm thickening fraction. DesignProspective, descriptive, cohort study SettingThe study was conducted in the Physiology and Respiratory Care Laboratory, Intensive Care Unit, Hospital Británico de Buenos Aires. ParticipantsThirteen healthy subjects >18 years old InterventionsHigh-flow nasal cannula oxygen therapy Main variables of interestDemographic data (age and gender), anthropometric data (weight, height, and body mass index), and clinical and respiratory variables (Diaphragm thickening fraction [DTf], esophageal pressure swing, respiratory rate [RR], esophageal pressure-time product per minute [PTPes/min]). ResultsMedian DTf decreased significantly as flow increased (P<.05). The baseline DTf measurement was 21.4%, 18.3% with 20 l/m, and 16.4% with 40 l/m. We also observed a significant decrease in RR as flow increased in HFNC (P<.05). In the 8 subjects with recordings, the PTPes/min was 81.3 cmH2O/sec/min (±30.8) and 64.4 cmH2O/sec/min (±25.3) at baseline and 40 l/m respectively (P=.044). ConclusionsThe use of high-flow oxygen therapy through nasal cannula of HFNC in healthy subjects decreases the DTf and RR in association with increased flow. In addition, the use of 40 l/m flow may reduce the muscular work associated with respiration.

Selectively enriching accessible quantum sieving sites in two‐dimensional carbons for D2/H2 kinetic separation

AbstractSeparation of hydrogen isotopes (D2/H2) attracts wide interest due to its important applications, such as nuclear fusion. Kinetic quantum sieving‐induced separation over tailored nanoporous solids is a promising method; however, the dynamic separation often shows a transient feature, thus a low D2/H2 selectivity even at temperature below 50 K. Herein, we selectively enriched the accessible quantum sieving (AQS) sites in two‐dimensional carbons by chemically growing a pore‐narrowing layer. The spatial density of such AQS sites is 8.5 times higher than that of commercial carbon molecular sieves. The kinetic selectivity of D2/H2 reached 4.6 at 77 K. Column breakthrough experiments revealed that the dynamic D2/H2 separation was enhanced by such a nanopore design. Aspen simulation indicated that D2 was enriched to 93.1% within 11 pressure swing adsorption cycles with a 1% D2/99% H2 mixture as feed.

Upgrading of Biogas Generated from Shrimp Processing Effluent Using Vacuum Pressure Swing Adsorption

Upgrading of Biogas Generated from Shrimp Processing Effluent Using Vacuum Pressure Swing Adsorption

Lab-scale pilot for CO2 capture vacuum pressure swing adsorption: MIL-160(Al) vs zeolite 13X

Carbon capture is among the key technologies to quickly reduce anthropogenic CO2 emissions to a net zero emission by 2050. Among the different separation technologies, adsorption is one of the most promising. Several Vacuum and/or Pressure Swing Adsorption cycles have been developed and tested for CO2 capture using mainly zeolite 13X. Metal organic frameworks, due to their exceptional tunability, can improve the performance of adsorption processes. Nevertheless, there is a lack of experimental results for these materials at pilot scale. To address this gap, a versatile VPSA lab-scale pilot (3 columns of 1.1 L) has been developed to evaluate adsorbents at kilogram scale for CO2 capture in various adsorption process configurations. The metal organic framework MIL 160(Al), synthesized and shaped at 60 kg, was also studied on this installation and compared to zeolite 13X with a 3-bed 6-step VPSA cycle for the separation of a 15/85 %vol of CO2/N2 mixture between 0.1 and 2 bar. Results obtained reveal purity of 90 % and recovery of 92.7 % for the MIL-160(Al) while zeolite 13X only reaches 79.7 % of purity and 85 % of recovery, proving the efficiency of this material for CO2 capture. These results contradict conventional indicators and demonstrate the importance of testing a material in VPSA cycle at kg scale to fully assess its performance.

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.

Understanding the adsorption properties of CO2 and N2 by a typical MOF structure: Molecular dynamics and weak interaction visualization

An extensible molecular dynamics (MD) force field for a typical metal–organic framework (MOF) has been developed and verified in comparison with experimental data. The visualization of the important weak interactions based on density functional theory (DFT) calculations is performed. The dynamic process of CO2 and N2 adsorption by MOF was then studied by MD methods. The gas adsorption and desorption during temperature and pressure swing were also investigated. It is found that the structural features of MOF have an important effect on the regional range and strength of the weak interactions, and the region of the van der Waals potential surface of the MOF can determine the gas density distribution. The adsorption is dominated by van der Waals interactions on the whole and the variation of the total weak interaction energy can reflect that of the adsorbed amount. The sorption/desorption responds more slowly to temperature swing than to pressure swing.

Plateau-Adapted Single-Pump, Single-Bed Vacuum Pressure Swing Adsorption Oxygen Generation Process Simulation and Optimization

To enhance the oxygen guarantee capacity in high altitude areas and address the challenges of traditional pressure swing adsorption oxygen generation fixed equipment with large volume and multiple device modules, a novel single-reversible-pump single-bed vacuum pressure swing adsorption (VPSA) oxygen generation process was proposed and simulated. This study investigated the effects of purge on oxygen productivity, purity, recovery, and energy consumption, determining that the optimum ratio of total oxygen in the purge gas to the total oxygen in the feed gas (P/F) was 0.176. A set of principle prototypes was developed and validated in plains. The process performance was then simulated and studied at altitudes of 3000 m, 4000 m, and 5000 m. Finally, the optimization was carried out by adjusting the product flow rate and feed flow rate, revealing that the best performance can be achieved when the oxygen purity exceeded 90% with lower energy consumption or larger productivity than the optimization goal. This study serves as a valuable reference for the optimization of the VPSA oxygen generation process in a plateau environment.

Feasibility of Different Methods for Separating n-Hexane and Ethanol

Conventional distillation methods cannot effectively separate the components of an azeotropic mixture since both phases have the same composition, thereby preventing further separation. Additional techniques such as pressure swing distillation or distillation with entrainers are often employed to overcome this limitation and achieve separation. The aim of this investigation was to select the most effective method for separating n-hexane and ethanol. The feasibility of three methods was analyzed: reduced pressure distillation, extractive distillation, and liquid–liquid extraction. The mutual solubility of n-hexane and prepared deep eutectic solvents (DESs) (nine hydrophilic: choline chloride with glycerol, ethylene glycol, or carboxylic acid (malic, citric, glycolic); tetramethylammonium chloride with glycolic acid; lactic acid with glycerol; K2CO3 with glycerol or ethylene glycol; two hydrophobic: menthol with decanoic or dodecanoic acid) was experimentally determined. Extraction experiments were conducted to test the solubility of DESs in the feed mixture. The effect of changing DES-to-feed mass ratio was further investigated with choline chloride–glycerol (1:2). The same DES and both hydrophobic DESs were able to increase the relative volatility and enhance the separation of ethanol and n-hexane. Based on the obtained results, extraction was selected as the most effective method for the separation of n-hexane and ethanol.

Vacuum pressure swing adsorption intensification by machine learning: Hydrogen production from coke oven gas

Hydrogen is a vital resource in the fight against climate change, and it has the potential to revolutionize the energy sector. Our research focused on optimizing the production of high-purity hydrogen using coke oven gas (COG), a valuable hydrogen source in the steel industry. By leveraging advanced artificial neural networks (ANNs), we can predict the performance and exergy efficiency of a 6-bed 12-step vacuum pressure swing adsorption (VPSA) process accurately and efficiently. The Pareto fronts were addressed by combining the evolutionary algorithm with ANNs, and the effects of operating parameters were discussed in detail. Importantly, we found that our VPSA process can achieve a hydrogen purity of 99.99% with 45.2% exergy efficiency. We also demonstrated that using ANNs can significantly enhance VPSA process optimization, making it a valuable tool for extracting high-purity hydrogen from COG.

Energy optimization of a non-aqueous solvent CO2 absorption system with pressure swing regeneration

This study focuses on optimizing the energy requirement in the post-combustion CO2 capture system using pressure swing regeneration through a model-based design (MBD). The simulation results highlight the significant impact of CO2 recovery, inlet gas and liquid flow rate, and CO2 concentration in the flue gas on the overall energy demand of the system. Moreover, an investigation into the de-sublimation chamber was undertaken, revealing a relationship between dry ice formation and the heat transfer between the LNG stream and CO2 in the heat exchanger. The parametric analysis study reveals that the sensible heat of the lean solvent is significantly influenced by the CO2 concentration in the liquid, consequently affecting the overall system energy. According to the results, the utilization of cold energy from LNG could save 80 % of the total energy requirement. The optimization results found the best working condition, which consumes energy of 0.190 GJ/ton CO2, 31 % lower than the basic scenario.

Separation of CO2/N2 onto Shaped MOF MIL-160(Al) Using the Pressure Swing Adsorption Process for Post-combustion Application

Separation of CO₂/N₂ onto Shaped MOF MIL-160(Al) Using the Pressure Swing Adsorption Process for Post-combustion Application