Swing Adsorption Technology Research Articles

Experimental study of four-step thermal swing adsorption cycle to upgrade biogas obtained from anaerobic digestion

Biogas is a renewable source of energy that when upgraded can be adopted as a reliable and sustainable alternative. This study evaluates the performance of thermal swing adsorption technology applying resistive heating, in upgrading biogas obtained from anaerobic digestion to biomethane. Commercial coconut shell-based activated carbon was used as an adsorbent in the four-step cycle process to capture carbon dioxide, using a fabricated adsorption model. The influence of minor gas constituents of biogas in carbon dioxide breakthrough curves was analyzed. Dynamic adsorption tests were carried out to evaluate the system performance in carbon dioxide capture. The maximum regeneration temperature of 60 ℃ was found to have peak carbon dioxide concentration of 39% in the waste gas, maximum energy requirements of 0.1538kWh per cycle, and an energy efficiency of 87%. This is a good trade-off between adsorbent recovery and system energy efficiency. The adoption of thermal swing adsorption technology in biogas upgrading systems is a viable alternative for water-deficient regions.

Breakthrough curves of H2/CO2 adsorptions on CuBTC and MIL-125(Ti)_NH2 predicted by empirical correlations and deep neural networks

With the continuous emergence of new materials, efficiently screening suitable materials for hydrogen purification by pressure swing adsorption (PSA) technology has become a hot topic. Metal-organic frameworks (MOFs) hold significant promise in gas adsorption and separation due to their unique structure and versatility. Breakthrough curves depict the dynamic adsorption kinetics of multi-components in fixed-bed columns, offering a means to screen adsorbents. In this study, a deep neural network (DNN) model comprising 11 hidden layers is developed to predict the dynamic breakthrough behavior of MOF CuBTC and MIL-125(Ti)_NH2 adsorbents. The training data for the DNN were generated from a non-isothermal model established using Aspen Adsorption software. Results demonstrate that the DNN model effectively predicts the H2/CO2 breakthrough behavior on CuBTC and MIL-125(Ti)_NH2 adsorbents. Compared with empirical mathematical correlation models, the DNN can predict breakthrough profiles under varying operating conditions, exhibiting superior adaptability. Furthermore, parametric studies based on the DNN model reveal that initial temperature, adsorption pressure and feed flow rate play important roles in the dynamic adsorption process, significantly influencing the position and shape of the breakthrough curve. Decreasing the feed flow rate and initial temperature while increasing adsorption pressure can enhance breakthrough times and hydrogen purity. By comparing the breakthrough curves of the two adsorbents under different operating conditions for H2/CO2, the dimensionless breakthrough time of CO2 on the CuBTC adsorbent was longer. Additionally, simulation results of the PSA cycle suggest that CuBTC yields higher hydrogen purity than MIL-125(Ti)_NH2. Consequently, CuBTC is deemed more suitable for hydrogen purification of binary H2/CO2 mixtures than MIL-125(Ti)_NH2.

Exploring enhanced CO2 separation from blast furnace gas: A multicolumn vacuum swing adsorption approach with process design and experimental assessment

Excessive emissions of carbon dioxide (CO2) are a major driver of global warming. Blast furnace gas (BFG) represents a major source of CO2 emissions in the steel industry, accounting for approximately 30 % CO2 emissions among the industry sectors. Hence, effective CO2 capture from BFG is imperative. This study presents an approach utilizing the vacuum swing adsorption (VSA) technology to capture CO2 from BFG. A 6-column VSA rig was designed and constructed to separate CO2 from a simulated BFG (CO2/N2 = 20 %/80 %) using zeolite 13X as adsorbents. The VSA process involved steps of adsorption, desorption, heavy product purge, light product re-pressurization, and pressure equalization. Five different process modes, i.e., 1-column and 3-step, 2-column and 6-step, 2-column and 8-step, 3-column and 9-step, and 4-column and 16-step configurations, were implemented to evaluate the influence of various process design factors on the separation performance. Additionally, a 6-column and 36-step process was devised to conduct a parametric study of VSA cycles by varying the adsorption duration and desorption pressure. Results revealed the pivotal role of heavy product purge and pressure equalization on the separation performance. The six-column process achieved a CO2 purity and recovery of 94 % and 82 %, respectively, with a energy consumption of 0.76 GJ/tonCO2 when employing a desorption step duration of 240 s and pressure of 8 kPa. In addition, a method of process optimization based on the bed capacity ratio, C, was introduced in this study, which provides a dimensionless quantity of the utilization of the adsorption column. Moreover, capturing CO2 from BFG through the VSA cycle not only enhances its heating value but also yields substantial advantages in terms of mitigating CO2 emissions.

Numerical modelling and simulation of methane enrichment: a systematic review on pressure swing adsorption technology

ABSTRACT Enriching methane from sources such as natural gas, biogas, and coalbed methane is a valuable gas separation endeavor, given methane as a cleaner and more sustainable fuel resource. Pressure swing adsorption (PSA) is widely regarded as a mature technology for this purpose. The essence of the mathematical model is to capture the fundamental aspects of the problem, enabling an accurate description of the system. This review summarizes recent trends in the mathematical modelling of PSA for methane enrichment. It provides a comprehensive compilation of numerical modelling and simulation studies, with a critical emphasis on methane enrichment applications. A rigorous mathematical model describing the adsorption phenomenology in a packed bed column is presented, incorporating mass, momentum, and energy balances, which serve as the fundamental framework for the cyclic adsorption process. Key analyses and performance metrics of PSA systems are detailed through examples from the literature. A case study based on a single column is presented to exemplify the mathematical modelling pathway and serve as a basis for model validation. The paper concludes by highlighting instructive avenues for future research directions and development in this area.

Simultaneously enhancing H2 recovery and CO2 captured pressure during the hydrogen purification process of medium-temperature shifting gas by coupled wet CO2 separation-PSA technology: From laboratory to industrial scale test

The petrochemical industry has a significant demand for high-purity hydrogen. It primarily obtained from the H2 purification unit by using pressure swing adsorption (PSA) technology to recover H2 from medium-temperature shifting gas (MTSG). The the coupled wet CO2 separation-PSA process was introduced in this work, aiming to capture CO2 from MTSG while simultaneously increasing the H2 recovery rate. To enhance the desorption pressure of CO2 separation unit in the coupled process to facilitate the storage or utilization of the captured CO2, firstly, a rigorous thermodynamic study was carried out to provide a theoretical basis for the development of an improved CO2 solvent. Subsequently, a pilot-scale test was executed to validate the theoretical findings. Finally, the patented coupled process was implemented at an industrial scale for the first time. The results showed that the capacity of PSA unit for H2 purification increased from 6800 to 12,000 tons per year and the H2 recovery rate increased from 84.6 % to 93.6 %; the CO2 desorption pressure increased from about 0.03 MPa (traditional Benfield process) to 0.15 MPa, which reduced the energy consumption of CO2 compression, and the total average annual economic benefits increased by US $ 15.55 million.

A Comprehensive Review on Biomethane Production from Biogas Separation and its Techno-Economic Assessments.

Biogas offers significant benefits as a renewable energy source, contributing to decarbonization, waste management, and economic development. This comprehensive review examines the historical, technological, economic, and global aspects of biomethane production, focusing on the key players such as China, the European Union, and North America, and associated opportunities and challenges as well as future prospects from an Australia perspective. The review begins with an introduction to biogas, detailing its composition, feedstock sources, historical development, and anaerobic digestion (AD) process. Subsequently, it delves into major biomethane production technologies, including physicochemical absorption, high-pressure water scrubbing (HPWS), amine scrubbing (AS), pressure swing adsorption (PSA), membrane permeation/separation (MP), and other technologies including organic solvent scrubbing and cryogenic separation. The study also discusses general guidelines of techno-economic assessments (TEAs) regarding biomethane production, outlining the methodologies, inventory analysis, environmental life cycle assessment (LCA), and estimated production costs. Challenges and opportunities of biogas utilization in Australia are explored, highlighting and referencing global projections, polarization in production approaches, circularity in waste management, and specific considerations for Australia. The review concludes discussing future perspectives for biomethane, emphasizing the importance of technological advancements, policy support, and investment in realizing its full potential for sustainable energy and waste management solutions.

Ion-exchanged commercial-zeolites for O2 production and CO2 capture by swing adsorption technology: a brief review

Ion-exchanged commercial-zeolites for O2 production and CO2 capture by swing adsorption technology: a brief review

The CO2 Capture System with a Swing Temperature Moving Bed

Abstract The reduction in CO2 emissions is now a very popular topic. According to the International Energy Agency, CO2 emitted in 2021 was 6% more than that emitted in 2020. Carbon capture and storage (CCS) is gaining popularity as a possible solution to climate change. Experts estimate that industry and power plants will be responsible for 19% of total CO2 emissions by 2050. This paper presents the design of a semi-industrial-scale system for CO2 capture based on the moving bed temperature swing adsorption technology. According to the results of laboratory tests conducted by the SINTEF industry, this technology demonstrates high capture efficiency (>85%). The CO2 capture medium involved in adsorption is activated carbon passing through individual sections (cooling, heating, adsorption), where CO2 is bonded and then released. The heat and mass transfer processes are realised on the developed stand. The heat exchangers use steam and water as the heating/cooling medium. The paper reviews the existing solutions and describes the developed in-house design of heat exchangers that will ensure heat transfer conditions being a trade-off between economic and efficiency-related issues of the CO2 capture process. The designed test stand will be installed in a Polish power plant and is expected to meet the method energy intensity target, set at ≤ 2.7 MJ/kg CO2, with a capture efficiency exceeding 85%. The aim of the work was to develop and solve technical problems that would lead to the construction of a CO2 capture station with parameters mentioned above. This stand uses an innovative method where CO2 is captured by contacting the fluid (gases) with solid particles. The heat exchange associated with the heating and cooling of the adsorbent had to be solved. For this purpose, heat exchangers were designed with high thermal efficiency and to prevent the formation of mounds.

Innovative dual-function system for efficient CO2 absorption and utilization: Local humidity swing fabric and microalgae-embedded hydrogel

In this study, we explored the use of local humidity swing (LHS) adsorption technology for carbon dioxide (CO2) capture from air, leveraging its low energy consumption and cost-effectiveness. By employing a coating technique, we immobilized ion exchange resin (IER) particles on fabrics with different hydrophilicities. The coating, consisting of silk fibroin (silk) and glycerol, formed a thin membrane on the fabric surface, effectively immobilizing the IER particles. The results revealed that hydrophobic polyester fabric with an initial silk concentration of 2 wt% (2 %SF/Gly@IER-PF) exhibited superior CO2 adsorption capacity (11.07 ml/g at 10 % relative humidity) and stability at varying humidities (10–90 %) compared to the hydrophilic cotton fabric. By covering the 2 %SF/Gly@IER-PF with a hydrophilic, highly water-absorbing non-woven fabric, one-way moisture transfer between the two types of fabrics was made, significantly affecting the water content and the release of adsorbed CO2 within the SF/Gly@IER-PF, and CO2 adsorption/desorption cycles could be achieved by detaching and attaching the water-absorbing fabric from the 2 %SF/Gly@IER-PF. The SF/Gly@IER-PF-based LHS system was combined with a silk/alginate composite hydrogel containing live microalgae, forming a dual-function CO2 fixation system. The functionalized fabric efficiently captured CO2 from the air, which was subsequently utilized by the gel-immobilized microalgae. As a result, the microalgae showed a higher proliferation rate compared to the control hydrogel system without the attachment of SF/Gly@IER-PF. This demonstrates the potential application of the dual-function system in effectively reducing CO2 levels from the air.

Pengembangan Konsentrator Oksigen Berbasis Empat Bahan Filtrasi Sebagai Solusi Inovatif Alat Bantu Pernafasan

Amidst the Covid-19 pandemic, there has been a significant increase in the demand for oxygen. More people require oxygen cylinders, yet the supply is insufficient to meet the community's needs. Oxygen Concentrators have become an essential device capable of producing pure oxygen with a purity level reaching 95% through the application of Pressure Swing Adsorption (PSA) technology. The resulting ratio produced by the concentrator is 33.4% for synthetic zeolite, 30% for silica gel, 20% for natural zeolite, and 26.7% for activated carbon.

Multi-objective optimization of breakthrough times for hydrogen purification through layered bed pressure swing adsorption based on genetic algorithm and artificial neural network model

Hydrogen purification from steam methane reforming (SMR) by pressure swing adsorption (PSA) technology is a common method to obtain high-purity hydrogen. The breakthrough time can well reflect the adsorption dynamics and help PSA cycle design. In order to avoid time-consuming and labor-intensive breakthrough curve experiments, it is very necessary to develop a fast and accurate surrogate model. In this study, a genetic algorithm (GA) and artificial neural network (ANN) are combined to predict and optimize breakthrough times of adsorbates in activated carbon/zeolite layered beds. Using the Latin hypercube sampling strategy, training data sets of GA-optimized ANN (GA-ANN) obtains from the physical model of adsorption, heat and mass transfer model. The genetic algorithm (GA) optimizes the weights and biases of ANN for better performance. The ANN topology has 4 input variables (superficial velocity, activated carbon height, adsorption pressure and feed temperature) and 3 output variables (breakthrough times of CH4, CO and CO2). The number of neurons in the hidden layer for the GA-ANN model was optimized as 7 to predict and optimize the maximum breakthrough time of SMR with a four-component (H2/CH4/CO/CO2) system. The sensitivity analysis displays that relative importance to the breakthrough time is in the order of superficial velocity (40.88%) > adsorption pressure (24.55%) > activated carbon height (21.04%) > feed temperature (13.53%). To obtain high-purity hydrogen, the GA-ANN model combined with multi-objective GA optimization is used to maximize the breakthrough times of CH4 and CO. The GA-ANN surrogate model proposed in this paper can not only accurately and quickly achieve the purpose of predicting the system breakthrough time with a high correlation coefficient (R = 0.9937) but also obtains the optimal operating conditions of PSA hydrogen purification.

Comprehensive performance and numerical analysis of pressure swing adsorption process-based medical oxygen concentrators under various operating conditions

ABSTRACT One common application of pressure swing adsorption technology is medical oxygen concentrator (MOC) which directly produces ~ 94% O2 from air. The operating condition determines the separation efficiency of MOC and is varied with practical requirements. A better understanding of performance, mass and heat transfer inside adsorption bed at wide operating conditions is of great importance. The impacts of key operating parameters on the performances, the concentration and temperature distributions of MOC have been numerically investigated. The numerical results demonstrate that high comprehensive performances are achieved at an optimal condition with combination of adsorption pressure, product and feed flowrate and feed temperature. As adsorption pressure increases, the front of gas concentration and temperature becomes sharp, which effectively benefits for improving the performance. It is nearly identical shapes of nitrogen concentration and gas temperature profiles after adsorption and the profiles are pushed forward near production end with increasing of product flowrates and decreasing of feed flowrates. The increasing of feed temperature is beneficial to improve the performance. However, the adverse mass transfer and thermal effects are dominant at very high pressures, flowrates and temperatures conditions and this variation increases the unit power of MOC.

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.

Waste to wheels: Performance comparison between pressure swing adsorption and amine-absorption technologies for upgrading biogas containing hydrogen sulfide to fuel grade standards

Waste to wheels: Performance comparison between pressure swing adsorption and amine-absorption technologies for upgrading biogas containing hydrogen sulfide to fuel grade standards

Simulation of working process of oxygen concentrator equipment by pressure swing adsorption

Oxygen is essential for human respiration and the existence of all living organisms. Medically it is used to treat diseases related to impaired respiratory function. In industrial scale, gaseous oxygen is separated from the air by liquefaction and fractional distillation techniques, while on a small and medium scale oxygen is usually separated by using zeolite molecular sieves and pressure swing adsorption (PSA) technology. During the Covid-19 pandemic, the demand for oxygen concentrators (PSA type) for personal and family use is very high. However, there isn’t any Vietnamese factory for production oxygen concentrator, so it is imported from abroad. In this paper, a pilot-scale oxygen concentrator was built at the Department of chemical process equipment, Hanoi University of Science and Technology. The operation of the device has been simulated and optimized on Aspen Adsorption software. The optimization parameters obtained will be used to design the equipment in industrial scale.

Pillared Clays as Cost-Effective Adsorbents for Carbon Capture by Pressure Swing Adsorption Processes in the Cement Industry

CO2 adsorption technology is gaining so much attention as a viable technique to mitigate the greenhouse effect. Having the appropriate adsorbent coupled with an optimized process design is the key issue toward its further development and wide industrialization. In the current work, we research two types of pillared clays, namely, aluminum oxide (Al-PILC) and zirconium oxide (Zr-PILC) applied in the pressure swing adsorption (PSA) technology for carbon dioxide capture in the cement industry. A comparison with the benchmark, zeolite 13X, is made. The first process analyzed is a two-stage system consisted of two beds, each stage operating in the Skarstrom cycle, where a techno-economic analysis is performed, including capital and operational costs. The Zr-PILC demonstrated the best performance with a purity of 76.6% and recovery of 72.1% in the first process design. The total annualized cost of CO2 for such a system is 25.71 €/ton avoided. Then, a six-bed system operating in a 6-1-4 adsorption cycle and a total of 18 steps is implemented. The best candidate Zr-PILC of the first process design is chosen as the adsorbent of the second design. The six-bed-PSA process has an annualized CO2 cost of 19.17 €/ton with a 78% of purity and 71.3% of CO2 recovery.

Active Fault-Tolerant Control Applied to a Pressure Swing Adsorption Process for the Production of Bio-Hydrogen

Pressure swing adsorption (PSA) technology is used in various applications. PSA is a cost-effective process with the ability to produce high-purity bio-hydrogen (99.99%) with high recovery rates. In this article, a PSA process for the production of bio-hydrogen is proposed; it uses two columns packed with type 5A zeolite, and it has a four-step configuration (adsorption, depressurization, purge, and repressurization) for bio-hydrogen production and regeneration of the beds. The aim of this work is to design and use an active fault-tolerant control (FTC) controller to raise and maintain a stable purity of 0.9999 in molar fraction (99.99%), even with the occurrence of actuator faults. To validate the robustness and performance of the proposed discrete FTC, it has been compared with a discrete PID (proportional–integral–derivative) controller in the presence of actuator faults and trajectory changes. Both controllers achieve to maintain stable purity by reducing the effect of faults; however, the discrete PID controller is not robust to multiple faults since the desired purity is lost and fails to meet international standards to be used as bio-fuel. On the other hand, the FTC scheme reduces the effects of individual and multiple faults by striving to maintain a purity of 0.9999 in molar fraction and complying with international standards to be used as bio-fuel.

Cost efficient oxygen concentrator with PSA technology

Normally atmospheric air contains mixture of gases like nitrogen (78%), oxygen (21%), and small amount of lot of other gases like carbon-di-oxide (0.03%), hydrogen. Oxygen concentrator is a device that concentrate (or) separate oxygen from ambient air by specifically removing nitrogen by process of Pressure Swing Adsorption (PSA). Pressure Swing Adsorption is a technique that separate oxygen from a mixture of gases depending on pressure to which molecular characteristics and affinity for a zeolite (Natrolite). The proposed output of Oxygen concentrator with Pressure Swing Adsorption technology is economical and high-efficient. The experimental results of the proposed system supplied the oxygen at the purity of about 94.7% for the low velocities of 0.5-3 L/min. It is concluded that the system provides a good performance when considered that a patient with the COPD should take the oxygen at the purity of 90% or more for the low velocities of 0.5-3 L/min. On comparing with other oxygen concentrator available in the market, this proposed system is highly cost effective and comparatively lesser in weight. As per the experiments conducted using the proposed system provides comparatively less noise and works efficiently for long time and oxygen purity is also high. Since, this proposed system has these many features. This is so much helpful for peoples who can’t able to afford market available oxygen concentrator.

Hydrogen production from coke oven gas using pressure swing adsorption process − a mathematical modelling approach

Coal is playing a major role as a reductant and as an energy source in the present world steel production due to its low cost and widespread distribution around the world. At the same time, being the largest contributor to global CO2 emissions, coal faces significant environmental challenges in terms of air pollution and global warming. Hydrogen is a promising alternative for coal in lowering the steel industry’s CO2 footprint, but the availability of green hydrogen is currently limited by its high production cost. This research study focuses on developing a pressure swing adsorption (PSA) technology that will allow for continued use of coal for a smooth transition towards green hydrogen-based steel production, by better utilisation of its by-product coke oven gas to produce high purity hydrogen. A generic, fast and robust simulation tool for simulating a variety of PSA processes considering both equilibrium and kinetic effects using a detailed non-isothermal and non-isobaric model is developed in the study. The adsorption equilibrium data required for the model are calculated from experimental results using the non-linear regression data fitting method. A series of rigorous parametric studies and breakthrough tests are performed using the developed mathematical model for better understanding of the effects of different factors on the PSA process performance. With the better understanding obtained from the above-mentioned parametric studies, the model is optimised by performing several simulation tests to achieve a high process performance in terms of purity and recovery of the H2 product, productivity of the adsorbents and energy consumption for compression of gases. The optimised 14-step multi-bed PSA cycle developed in this study allows for an improved energy efficiency of coal usage by better utilisation of its by-product coke oven gas by converting it into valuable high purity (>99.999%) hydrogen product with a recovery of over 75%.

Out of breath in pandemic - Is pressure swing adsorption (PSA) technology a solution for saving lives?

In these unprecedented times of COVID-19 pandemic, globally there has been a shortage of medical supplies, hospital beds, health care workers, etc. This was accentuated in India with a shortage of oxygen in the second wave of pandemic. The reasons for shortage were mainly imbalance between demand-supply and these also led to implementation of ingenious solutions in the form of oxygen generators based on PSA technology. The technology was an off shot from OBOGS developed by DRDO and DEBEL for light combat military air crafts. This review discusses the scientific technology behind medical oxygen plants based on PSA, its applications and its advantages to combat the dearth of oxygen.