Temperature Swing Adsorption Research Articles

Design and development of an advanced gas storage device and control method for a novel compressed CO2 energy storage system

Compressed CO2 energy storage (CCES) has advantages over compressed air in energy density and efficiency. Compared to air, CO2 needs to be in a closed-loop cycle in the CCES. The development of CCES is constrained by low-pressure CO2 storage. Storage density can be increased by adsorption without changing pressure. However, the control of the flow rate during adsorption/desorption has rarely been studied experimentally. In this paper, an adsorption tower for CCES is proposed and the regulation of the desorption flow rate is experimentally investigated. Using temperature-swing adsorption, the storage and release can be regulated without reducing the energy storage capacity. During the desorption process, the temperature of the exhaust gas can also be maintained stably. The adsorbent with a volume of 51.81 L was able to release 6121.9 g of CO2 when heated to 200 °C. Under the same pressure conditions, the effective storage density of the tower can reach 118.2 g/L, which is 67.5 times higher than the gaseous density (1.75 g/L, 1 bar, 303 K). The desorption flow rate is linearly related to the forward speed of the front in the adsorption tower. The flow rate can be regulated by controlling the superficial gas velocity and the desorption temperature. This method can match the flow rate of the adsorption tower with the gas consumption of the compressor, providing a novel solution for CCES.

A multi-scale method for the study of deep drying of ethylene with 3A zeolite

Coal-based ethanol to ethylene (ETE) is an emerging production pathway with the advantages of a short construction period, high product purity, and few by-products. N2 is commonly used in industry to regenerate zeolites during the ETE process, with the problems of excessive material consumption, energy consumption and environmental pollution. To solve this problem, this paper proposed a method of using the ethylene product as regeneration gas to regenerate the zeolite and recover the desorbed gas. In this work, we adopted a multi-scale simulation method combining microscale apparent diffusivity and macroscale mass transfer models. Reactive force field and molecular dynamics (ReaxFF-MD) were used to obtain an equation for the diffusion coefficient versus temperature. The start-up of the twin-tower temperature and pressure swing adsorption (TPSA) process was simulated using Computational Fluid Dynamics (CFD). The TPSA process achieved an outlet water content below 5 ppm, fulfilling the process specifications.

Addressing small-scale temperature swing adsorption challenges using intensified fluidised bed technology for carbon capture process development

Polyethylenimine (PEI)-based adsorbents exhibit high CO2 capacities, making them potential candidates for mitigating unavoidable industrial CO2 emissions. However, desorption of CO2 from PEI, and from adsorbents in general, has received far less attention in the literature than adsorption. Whilst Temperature Swing Adsorption (TSA) is simple to conceptualise, it is difficult to implement in small-scale experiments in practice. Here we study the desorption characteristics of a commercial branched PEI adsorbent in a small-scale swirling fluidised bed reactor (TORBED) to improve the small-scale heat transfer rates. Our experimental results show that higher desorption temperatures, higher gas flow rates, and higher CO2 concentrations during adsorption can improve the desorption efficiency (defined as the amount of CO2 removed as a fraction of the initial amount adsorbed). In terms of kinetics, we found that the fractional order kinetic model provided the best fit to the PEI adsorbent, implying that this adsorbent involves multiple simultaneous molecular interactions, physisorption processes, and chemisorption processes, that cannot be described by simpler pseudo 1st or 2nd order models. Desorption rates in the TORBED in this study were 1 order of magnitude faster than fluidised beds, and 2–3 orders of magnitude faster than packed beds.

Techno-economic assessment for the practicability of on-board CO2 capture in ICE vehicles

The transport sector is a major energy-intensive and significant contributor to CO2 emissions. With heavy-duty internal combustion engine vehicles (HD-ICEVs) set to remain a primary mode of transport for goods and passengers, the European Union plans to implement CO2 emission rights starting in 2027 to address this issue. To mitigate CO2 emissions, on-board carbon capture technologies can be an innovative solution, but a comprehensive analysis from several perspectives must be carried out. To tackle the existing knowledge gap on this subject, this paper presents the techno-economic assessment of a CO2 capture and storage system hybridised with an organic Rankine cycle (CCS-ORC) integrated into an HD-ICEV whose technical ability has been previously demonstrated. In this paper, the capture installation based on temperature swing adsorption is designed for two engines with different displacement volumes, at varying carbon capture rates (CCR), and using three different sorbents. The size of the thermal devices is estimated as the determinant factor for the required space and the installation costs. The results show that the heat exchangers can achieve a minimum area density of 100 m2/m3, while the most significant temperature swing adsorption device obtained is scarcely 0.26 m3. The carbon abatement cost (CAC) obtained for the CCS-ORC system is less than 35 €/tCO2 at 100 % of CCR, and with an engine size greater than 18 and 21 L, the CAC of the CCS-ORC system is zero at 100 and 70 % of CCR, respectively. Furthermore, with a CO2 emissions right price above 71 €/tCO2, the projected payback of the initial investment of the CCS-ORC system is achieved in the lifespan of the HD-ICEV for all sorbents evaluated at 100 % of CCR.

Preparation of isoreticular MIL-101(Cr) based on pre- and post-synthetic strategy and study for carbon dioxide capture

The functionalization of MIL-101(Cr) presents a formidable challenge when employing covalent bonds, due to the inherent difficulty of incorporating reactive organic groups into its structure. In this work, we have successfully synthesized MIL-101-CHO tagged with formyl by adopting a pre-synthetic strategy, utilizing 3‑hydroxy-1-oxo-1,3-dihydroisobenzofuran-5-carboxylic acid as the key ligand. Then the integrity of the formyl group and the phase purity of the resulting MIL-101-CHO were rigorously confirmed through FT-IR and 1H NMR characterization. Employing post-synthetic strategy, four amine-MOFs were prepared through cascade reaction of Schiff-base condensation and NaBH4 reduction. The CO2 adsorption properties of all isoreticular MIL-101(Cr) materials were thoroughly investigated. Notably, MIL-101-TAEA demonstrated exceptional performance, with the highest Qst 70.1 kJ/mol at low coverage, the best adsorption capability 2.34 mmol/g at 298 K under 1 bar CO2, and the selectivity 172 for CO2/N2. Furthermore, the good regenerability of MIL-101-TAEA was proved by the CO2 temperature swing adsorption tests. Ultimately, MIL-101-TAEA maintain 60 % performance for trace CO2 capture after 16 cycles under the mimic atmosphere conditions, showing its potential for practical applications in gas separation and capture technologies.

Troubleshooting of an Industrial Ethane Treatment Unit: Ultradilute CO2 Adsorption from Ethane Stream by a Temperature Swing Adsorption Process

Troubleshooting of an Industrial Ethane Treatment Unit: Ultradilute CO₂ Adsorption from Ethane Stream by a Temperature Swing Adsorption Process

Solar-driven high-performance biomass porous carbon for efficient CO2 capture

Temperature swing adsorption (TSA) based on solid adsorbents is an efficient CO2 capture technology, but the temperature swing process is energy-intensive. Utilizing solar energy to regenerate adsorbents during the CO2 swing adsorption process can decrease energy consumption. This work reports a novel high-performance biomass porous carbon for efficient CO2 capture and separation in the solar-driven TSA process. Inspired by the distinctive internal expansion structure of succulents, the adsorbent is synthesized using succulents as precursors with a large specific surface area (1715 m2/g) and high solar absorbance (90.38 %), resulting in high CO2 adsorption capacity and solar thermal conversion capacity. It achieves a remarkable working capacity of 30.94 mg/g at a low desorption temperature (60 °C) in the solar-driven TSA process with a light intensity of 600 W/m2, 80.7 % higher than commercial activation carbon. The proposed biomass porous carbon derived from succulent plants has substantial potential for application in the solar-driven TSA process.

Synthesis of biomass combustion fly ash derived zeolites for CO2 adsorption: Optimisation of hydrothermal synthetic pathway

Industrial biomass combustion fly ash has been investigated as a precursor for zeolites with a view to evaluate the potential for adsorption of CO2. The synthesis methodology has been optimised via Design of Experiment by employing a Taguchi L9 array. Three variables were identified as statistically significant, the crystallisation temperature, crystallisation time and the liquid to solid ratio. Analysis of the main effects revealed an optimum set of conditions which produced a sample with the highest adsorption capacity of those prepared, 1.84 mmol g−1 at 50 °C. This was a result of the conversion of the as-received fly ash into type A (LTA) and type X (FAU) zeolites after alkaline fusion with NaOH and hydrothermal treatment. The enthalpy of adsorption was estimated at -40.2kJmol−1 and was shown to be dependent on surface coverage; the isosteric enthalpy of adsorption at zero coverage was -86 kJ mol−1. The working capacity of the adsorbent was maintained at 85 % of the first adsorption uptake after a total of 40 cycles in a simulated temperature swing adsorption process (50 °C/150 °C adsorption/desorption). The equilibrium and kinetic CO2 adsorption isotherms are presented and modelled through non-linear regression to reveal the adsorption mechanisms demonstrated by the fly ash-derived zeolites. Significant heterogeneity exists within the multi-phase zeolite which presents both micro and mesoporosity. The developed adsorbent presents a feasible route to valorisation of biomass combustion fly ash with good potential for application in the separation of CO2.

Polymer-grade propylene production through temperature swing adsorption: Molecular simulation and techno-economic analysis

Producing polymer-grade propylene from the propylene-rich mixtures can be quite challenging since the most commonly employed technology, distillation, requires high-energy input and is expensive. Therefore, identifying less-costly, efficient, and environmentally friendly methods, such as the use of the adsorptive process, is highly desirable. In this regard, six pure silica zeolites (AFV, AST, AVL, IFR, LEV, and SWY) as propane selective adsorbents are investigated for the separation of 10 mol.% propane and 90 mol.% propylene mixture. Molecular simulation Monte Carlo (MC) is used to calculate framework structure parameters such as pore volume, surface area, and framework density of pure silica zeolites. Also, adsorption isotherms, propane selectivity, and working capacity are presented using MC calculations. The Langmuir-Freundlich isotherm model is utilized to calculate isotherm parameters. A system model is implemented in Aspen Adsorption software (version 11) and breakthrough curves are achieved. The Temperature Swing Adsorption (TSA) cycle is simulated and key performance parameters such as propylene purity, recovery, and productivity for all six silica zeolites are calculated. Finally, economic analysis of the TSA process is performed using the Aspen Capital Cost Estimator (version 11) and Aspen Process Economic Analyzer (version 11) and compared with the cost of the conventional distillation process. Results showed that the capital cost and operating cost of temperature swing adsorption are 42.3 % and 91.37 % less than those of distillation, respectively.

Process design and adsorbent screening of VSA and exchanger type VTSA for flue gas CO2 capture

Carbon capture, as a core technology for mitigating greenhouse gas emissions, the greatest challenge is the balance between separation performance and energy consumption. This study seeks to evaluate and screen the separation performance and energy consumption of four typical adsorbents (13X, Mg-MOF-74, activated carbon, and Lewatit VP OV 1065) in vacuum temperature swing adsorption (VTSA) and vacuum swing adsorption (VSA) through optimization approach, which will support in-depth research and decision-making on adsorption processes. A non-isothermal non-adiabatic numerical model was carried out to describe a novel 4-bed 10-step VTSA cycle developed on an exchange type adsorption unit (ETAU), and the model was validated by binary breakthrough and temperature swing experiments. A 4-bed 10-step VSA cycle was in turn established and investigated. Parametric analysis of the two cycles was performed by varying the operating variables including feed gas flow rate, recycle time, and purge-to-feed ratio. Process optimization of the multiplicative fraction evaluation function, simultaneously considering purity, recovery, and productivity, was achieved using a dual convergence algorithm. Results showed that all four adsorbents could achieve more than 90 % purity and recovery on the VTSA process employing the ETAU for post-combustion carbon capture, and the separation performance was substantially superior to that of the VSA cycle. Mg-MOF-74 obtained a CO2 product with 97.90 % purity, 98.48 % recovery, and 5.48 mol/kgads/hr productivity at a desorption temperature of 383.15 K; it has a specific heat consumption of 1.45 GJth/ton and a specific power consumption of 0.55 GJel/ton. The total energy consumption of 13X was slightly lower than that of amine adsorbents, giving 95.00 % purity, 97.60 % recovery, and 1.91 mol/kgads/hr productivity. Relatively low desorption temperature is expected to introduce ultra-low-grade waste heat for partial heat source substitution, contributing to the energy sustainability of adsorption carbon capture technology.

Rapid and Accurate Screening of the COF Space for Natural Gas Purification: COFInformatics.

In this work, we introduced COFInformatics, a computational approach merging molecular simulations and machine learning (ML) algorithms, to evaluate all synthesized and hypothetical covalent organic frameworks (COFs) for the CO2/CH4 mixture separation under four different adsorption-based processes: pressure swing adsorption (PSA), vacuum swing adsorption (VSA), temperature swing adsorption (TSA), and pressure-temperature swing adsorption (PTSA). We first extracted structural, chemical, energy-based, and graph-based molecular fingerprint features of every single COF structure in the very large COF space, consisting of nearly 70,000 materials, and then performed grand canonical Monte Carlo simulations to calculate the CO2/CH4 mixture adsorption properties of 7540 COFs. These features and simulation results were used to develop ML models that accurately and rapidly predict CO2/CH4 mixture adsorption and separation properties of all 68,614 COFs. The most efficient separation process and the best adsorbent candidates among the entire COF spectrum were identified and analyzed in detail to reveal the most important molecular features that lead to high-performance adsorbents. Our results showed that (i) many hypoCOFs outperform synthesized COFs by achieving higher CO2/CH4 selectivities; (ii) the top COF adsorbents consist of narrow pores and linkers comprising aromatic, triazine, and halogen groups; and (iii) PTSA is the most efficient process to use COF adsorbents for natural gas purification. We believe that COFInformatics promises to expedite the evaluation of COF adsorbents for CO2/CH4 separation, thereby circumventing the extensive, time- and resource-intensive molecular simulations.

Life cycle assessment of post-combustion carbon capture and storage for the ultra-supercritical pulverized coal power plant

In this paper, different emerging post-combustion technologies, i.e., monoethanolamine (MEA), aqueous ammonia, pressure swing adsorption (PSA), temperature swing adsorption (TSA), membrane and calcium looping, were applied to an ultra-supercritical coal-fired power plant for carbon capture. A ‘cradle-to-grave’ life cycle assessment (LCA) was conducted to evaluate the technical performance and environmental impacts of the power plant with six emerging carbon capture technologies. Carbon capture significantly influences the impact categories directly associated with flue gas emission. The application of carbon capture reduced the GWP in the range of 49–75 %. TAP also reduced in the range of 18–51 %. However, the human toxicity potential, eutrophication potential, ecotoxicity potential and particulate matter formation potential increased due to energy and resource consumption in the upstream and downstream processes. For the life cycle water consumption potential, it decreased by 8 % with calcium looping, whereas it increased in the range of 36–75 % with other post-combustion technologies. The highest reduction in GWP and the least reduction in power efficiency was observed in calcium looping because of the high-temperature heat recovery from flue gas and elimination of complex solvent manufacturing. The plant with aqueous ammonia and membrane separation had the second and third highest reductions in GWP. In addition, the lowest values for TAP, FEP, and MEP were obtained in the membrane system. With MEA for CO2 capture, the total GWP value of the plant is slightly higher than these three technologies mentioned above, and the highest HTPc, FETP, and METP can be observed in this case. TSA and PSA have the most significant environmental impacts in most categories due to higher energy requirements.

Probing the differences in CO2 adsorption/desorption behaviors of solid amine sorbents in fixed and fluidized beds

Circulating fluidized bed temperature swing adsorption (CFB-TSA) CO2 capture process using solid amine sorbents has become a widely recognized solution to reduce stationary sources CO2 emissions. The successful design and operation of the adsorber and desorber requires much information on the CO2 adsorption and desorption behaviors of the sorbents in fluidized bed reactors. However, among the existing studies, little attention has been paid to desorption performance, which is equally important as adsorption performance. And almost all of them were conducted in TGAs or fixed beds, the lack of research in fluidized beds making it difficult to guide the design of industrial fluidized bed reactors. In addition, the systematic comparison of the above-mentioned adsorption/desorption behaviors and bed hydrodynamics (e.g. pressure drops) in fixed and fluidized beds can help provide theoretical support for the optimization of adsorbers, desorbers and coolers, which has not been reported yet. Therefore, we for the first time investigated the CO2 adsorption/desorption behaviors as well as hydrodynamics in both fluidized and fixed beds using a solid amine sorbent in a temperature swing adsorption (TSA) experimental rig. The results show that the sorbent exhibits faster adsorption and desorption kinetics in fluidized beds than those in fixed beds, as reflected by the fitted parameters of the Avrami kinetic model and the change of bed temperature during adsorption and desorption tests. And the bed pressure drops in fluidized beds are also much lower than that in fixed beds, especially at high superficial gas velocities and high sorbent loadings. By further discussion, a fluidized bed can also achieve lower equipment investment and less sorbent loading compared to multiple fixed beds in parallel. This study demonstrates the advantages of fluidized beds over fixed beds in large-scale TSA units in view of higher reactor efficiency, lower energy consumption and equipment investment.

Techno-economic comparisons of CO2 compression and liquefaction processes with distillation columns for high purity and recovery

CO2 compression and liquefaction (CCL) requires recovery to be optimized under purity constraints for transportation and storage to minimize costs. CCL processes that operate at 1 million t/y were techno-economically analyzed to evaluate the levelized cost of CO2 liquefaction (LCCL) and to examine the effect of carbon taxes on the LCCL. The processes included multistage compressors, temperature swing adsorption (TSA) for dehydration, and distillation columns for impurity removal. The same purity constraints were applied to four CCL processes that produce liquid CO2 at 80 bar and 40 °C: (i) a CCL process without a distillation column (Reference case), and CCL processes with distillation columns placed after (ii) the seventh compressor (Case 1), (iii) the sixth compressor (Case 2), and (iv) the TSA unit (Case 3). The reference case failed to meet purity requirements, delivering an LCCL of $16/t-CO2. On the other hand, Case 1 was the most cost-efficient among the three cases, delivering a minimum LCCL of $22/t-CO2 at a recovery of 93 %, which is consistent with usual costs ($13–25/t-CO2). Charging a carbon tax of $100/t-CO2 on CO2 emissions during the CCL process increased the minimum LCCL to $25/t-CO2 for Case 1 and shifted the optimum recovery to 96 %.

Thermal energy storage integration for increased flexibility of a power plant with post-combustion CO2 capture

Flexible operation of thermal power plants will become increasingly relevant in the coming years. This work evaluates the effect of integrating a steam accumulator into a 598 MW supercritical coal-fired power plant with moving bed temperature-swing adsorption CO2 capture. Charging the accumulator with reheat steam from the turbine train can reduce the net power output by up to 1.4 % (8.2 MW) for around 200 min. Small charging flow rates are recommended to maximize the final pressure of the accumulator. Covering the sorbent regeneration duty and meeting the demand of two feedwater heaters were considered as alternatives for discharging of the accumulator. Thermal storage discharging was found to give relative power plant load increases between 1.7 and 11.2 % (10.2–66.9 MW) for up to 37.5 min, which exceeds the requirement for primary reserve. Increases in the electrical energy output of 10.5–11 MWh were achieved. The flexibility modes studied in this work are compatible with high CO2 recovery rates.

CO2 capture from flue gases in a temperature swing moving bed

This paper presents a test stand for the capture of CO2 from flue gases arising due to firing pulverised hard coal. The stand, financed from the 2014–2021 Norway Grants, is installed at a Polish power plant. The innovation of the proposed CO2 capture method, developed by the Norwegian partner in the project (SINTEF Industry), lies in the use of activated carbon in the process of temperature swing adsorption in a moving bed. The paper also presents preliminary results of numerical simulations performed using the General PROcess Modelling System (gPROMS) software. The simulations concerned the operation of a supercritical power unit combined with a system for capturing CO2 from flue gases. Transient operation of the system was analysed, assuming rapid changes in the power unit load. Special attention was paid to the CO2 capture process energy consumption at an increase in load by 5% of the power unit nominal capacity in 30 s. It is found that the proposed CO2 capture method “keeps up” with such rapid load changes at the method energy consumption smaller than 2 MJ/kg CO2.

Quantitative analysis on chemical influence of modified activated carbon in TSA/PSA for methanol via alterable phosphorus functional groups and stable structure

Volatile organic compounds (VOCs) emissions cause serious health problems and environmental pollution, and modified activated carbon is widely used in the treatment of VOCs pollution. Methanol was selected as adsorbate and activated carbon with alterable phosphorus functional groups was synthesized as adsorbent. In the absence of the influence of the physical properties, the chemical functional groups influence coefficient (AC) was proposed, which can be used to analysis and predict the influence of chemical functional groups specially. The results show that the performances including adsorption capacity and enrichment ratio are positively related to the AC whether in temperature swing adsorption (TSA) or pressure swing adsorption (PSA). By comparison, the adsorption capacity of PSA is greater than that of TSA because of the higher efficiency caused by faster cycle. Further research on process showed that the curve character of TSA, including breakthrough time and equilibrium time, is highly related with AC, but the curve character of PSA is mainly depended on the state of activated carbon. Therefore, the attenuation of TSA is mainly caused by the change of chemical functional groups, while the attenuation of PSA is mainly caused by the failure of activated carbon.

Process-performance of solid sorbents for Direct Air Capture (DAC) of CO2 in optimized temperature-vacuum swing adsorption (TVSA) cycles

The process performance of three amine-functionalized chemisorbents (TRI-PE-MCM-41, SI-AEATPMS, APDES-NFC-FD-S) and two physisorbents (SIFSIX-18-Ni-β and NbOFFIVE-1-Ni) was evaluated for direct air capture (DAC) of CO2 in temperature-vacuum swing adsorption (TVSA) and steam-assisted temperature-vacuum swing adsorption (s-TVSA) cycles. Rigorous process optimizations were performed to evaluate the trade-off between energy consumption and productivity. Thermal energy consumption, with main contributions arising from desorption of CO2 and H2O, sensible heat of solids, is higher than electrical energy. While steam purge generally improves productivity at the cost of energy, an exception was noticed where it was also found to reduce energy. For the sorbents studied, minimum energy and maximum productivity ranged between 6.25–30.4 MJth/kgCO2, and 0.01–0.15 TPD of CO2/m3 of sorbent, respectively. For all the sorbents, while target CO2 purity (≥95%) can be achieved with moderate vacuum pressure (≈0.30 bar), low regeneration pressures (≈0.050 bar) can lower energy demand and increase productivity. A new ambient pressure temperature swing adsorption cycle is introduced. This cycle achieves target purities, albeit at higher energy consumption compared to those that use vacuum. The study showed that physisorbents, generally not studied for DAC, can be promising. Parametric studies revealed that the lack of multi-component thermodynamic and kinetic data impedes the objective evaluation of DAC processes.

Layered Double Hydroxide Nanoparticles/Microparticles (Mg/Al = 2) as Adsorbents for Temperature Swing Adsorption: Effect of Particle Size on CO2 Gas Evolution Behavior

Layered Double Hydroxide Nanoparticles/Microparticles (Mg/Al = 2) as Adsorbents for Temperature Swing Adsorption: Effect of Particle Size on CO₂ Gas Evolution Behavior

CO2 capture feasibility by Temperature Swing Adsorption in heavy-duty engines from an energy perspective

This study made an energy performance analysis and an estimate of the volume and weight of an innovative carbon capture and storage (CCS) system by temperature swing adsorption (TSA) hybridised with an organic Rankine cycle (ORC) working with the waste heat contained in the exhaust gases of a natural gas engine. To achieve this, two varying-sized engines are simulated across the entire rpm range and under partial engine loads. Subsequently, energy simulations are conducted at two CO2 capture rates (CCR) and employing three sorbents (MOF-74-Mg, PPN-6-CH2-DETA and activated carbon) to compare the CCS-ORC performance. Results demonstrate the viability of installing CCS-ORC systems in heavy-duty vehicles since they require less than 6 % of the total volume of the studied vehicles. The engine power penalty induced by the CCS-ORC system varies from 1.9 % with MOF-74-Mg to 23.5 % with activated carbon at 100 % of CCR, leading to a maximum 6.14 % rise in engine fuel consumption. Finally, the maximum CO2 capture process energy consumption is 631 kJ/kgCO2, 9.9 % lower than the literature reported for TSA. Based on these promising results, applying the hybridised system presented in this paper for CO2 capture in sectors that use heavy-duty engines is a strategy to implement.