Temperature Swing Adsorption Research Articles

Linking the effect of temperature on adsorption from aqueous solution with solute dissociation

Imperative decarbonization of water purification processes entails alternative regeneration methods for activated carbon. Regeneration based on changing dissociation equilibria, i.e. a major influencing factor on adsorption, usually requires the addition of acids/bases, but may also be triggered by temperature swing. Although adsorption and dissociation are both temperature-dependent phenomena, their conjunction has received little attention regarding trace organic compounds (TrOCs) and large temperature intervals, in particular above ΔT ≥ 50 ∘C. Therefore, we studied the adsorption equilibria of 16 TrOCs onto one granular activated carbon at temperatures ranging from 20 to 95 ∘C. The majority of compounds (12/16) exhibited an exothermic apparent adsorption enthalpy, while 3 out of 16 exhibited an endothermic apparent enthalpy. The range spanned from − 46 to + 50 kJ mol−1 (median at − 17 kJ mol−1). The possible origins of endothermic adsorption were discussed. A rationale of shifting pKa and thus changing dissociation of TrOCs was introduced and traded off against existing rationales, i.e. changing solute solubility, changing adsorption heat capacity, and saturation effects of the adsorbates. This knowledge may allow designing temperature swing adsorption processes that unlock the dissociation switch. The augmented process efficiency can thus provide the foundation for low-carbon emission, circular water purification processes.

Performance comparison of three adsorption cycles for CF4 recovery from waste gas using 13X zeolite

CF4 is one of the most influential greenhouse gases. With the development of the microelectronics industry, the emission of CF4 waste gas increases sharply. The adsorption method for CF4 recovery from waste gas can bring both environmental and economic benefits. However, most of the existing studies on the CF4 recovery by adsorption focus on the properties of adsorbents, and the related studies on the recovery cycle are just starting. But the better cycle performance can be got only by considering the characteristics of the cycle. In this paper, the molecular simulation method of Grand Canonical Monte Carlo is used to calculate the adsorption equilibrium isotherm of CF4 on zeolite 13X. An equilibrium model of the adsorption cycle is developed, and the cycle performance of temperature swing adsorption (TSA), pressure and temperature swing adsorption (PTSA) and vacuum and temperature swing adsorption process (VTSA) are optimized. The relationship between evaluation index (purity, recovery rate, exergy efficiency) is analyzed. The optimal performance of the three cycles is compared. It is found that the adsorption temperatures corresponding to the optimal Pareto solutions of the three cycles are all around 273 K. In the solution set of optimal cycle performance of the three cycles, the purity and recovery rate show a nearly linear positive correlation. Both the purity and the recovery rate are in a competitive relationship with the exergy efficiency. In the VTSA cycle, when the purity is greater than 0.795, the exergy efficiency drops rapidly as the purity increases. The optimal value of the performance index of each cycle is sorted as VTSA > PTSA > TSA. Only an increase in CF4 adsorption capacity within 6 times can increase the optimal purity and exergy efficiency by around 0.15, but it can only increase the recovery rate by 0.03.

A fast methodology to rank adsorbents for CO2 capture with temperature swing adsorption

A new methodology for evaluating different commercial adsorbents for CO2 capture using temperature swing adsorption (TSA) has been developed. The screening method is based on thermogravimetric analysis (TGA) combined with differential scanning calorimetry (DSC) to study the cyclic behavior of adsorbents paying attention on CO2 production and desorption energy. CO2 production and desorption energy were determined for commercial zeolites using a simulated flue gas (15% CO2 / 85% N2 v/v). Binderless zeolites had better CO2 production and lower desorption energy on TSA cycles than their analog binder-based zeolites. The zeolite with the highest CO2 production (0.077 kgCO2/kgads٠h) and the lowest desorption energy (0.56 kWh/kgCO2) was the 13XBL binderless zeolite. On the other side, the 5A zeolites (binder and binderless) had the lowest CO2 production (0.046–0.054 kgCO2/kgads٠h) and the highest desorption energy (0.78–0.93 kWh/kgCO2) among zeolites. Results obtained demonstrated that the proposed methodology is a good basis for the fast selection of the best adsorbent and for the selection of the adsorption and desorption cycling temperatures in CO2 capture processes through TSA.

C4+ Liquid Recovery from Natural Gas by Temperature Swing Adsorption Followed by Liquefaction of Heavy Extracted Product

C4+ Liquid Recovery from Natural Gas by Temperature Swing Adsorption Followed by Liquefaction of Heavy Extracted Product

Degradation of Desiccants in Temperature Swing Adsorption Processes: The Temperature Dependent Degradation of Zeolites 4a, 13x and Silica Gels

Degradation of Desiccants in Temperature Swing Adsorption Processes: The Temperature Dependent Degradation of Zeolites 4a, 13x and Silica Gels

Sorbent-Coated Carbon Fibers for Direct Air Capture Using Electrically-Driven Temperature Swing Adsorption

Sorbent-Coated Carbon Fibers for Direct Air Capture Using Electrically-Driven Temperature Swing Adsorption

Study on Coconut Shell Activated Carbon Temperature Swing Adsorption of Benzene and Formaldehyde

Adsorption can be used to recover effectively the volatile organic gases (VOCs) in the exhaust gas from factories through using an appropriate adsorption bed. Due to form a physical or chemical bond, adsorption occurs between the porous solid medium and the liquid or gas multi-component fluid mixture. The regeneration capacity of the adsorbent is as important as the adsorption capacity and it determines the economics of the adsorption system. The regeneration of adsorbent can be realized through changing the pressure or temperature of the system. Here, activated carbon samples from coconut shell were prepared and characterized. Benzene or formaldehyde in the mixed air was used as the adsorption object, and the adsorption experiment was carried out in a U-shaped bed. Discussed how adsorption was affected by activated carbon type, adsorbate and temperature. The results show that oxidation modified activated carbon can increase the adsorption effect of formaldehyde, but will reduce the adsorption effect of benzene, because their adsorption mechanism is different. At 30°C, the saturated adsorption capacity of AC-0 for benzene is 437.0 mg/g, and that of AC-1 for formaldehyde is 670.5 mg/g. In the experimental range, it is found that the adsorption capacity increases with the decrease of temperature, and their changes are very consistent with the fitted ExpDecay1 function.

Increased flexibility of coal-fired power plant with moving bed temperature-swing adsorption CO2 capture by use of thermal energy storage

Increased flexibility of coal-fired power plant with moving bed temperature-swing adsorption CO2 capture by use of thermal energy storage

A metal-organic framework (MOF)-based temperature swing adsorption cycle for postcombustion CO2 capture from wet flue gas

We report a simulation-based feasibility study of a single-stage temperature swing adsorption (TSA) process operated on a metal–organic framework (MOF) adsorbent, UTSA-16, for CO2 capture and concentration from a wet flue gas without pre-drying or a desiccant pre-layer. Two cycles comprising four and five-steps are compared. A non-isothermal and non-isobaric in-house simulator including suitably modelled equilibrium and kinetics of H2O-CO2-N2 ternary system is used to investigate the cyclic processes. The variables investigated are moisture-saturated flue gas at two feed and three regeneration temperatures. Both TSA cycles can meet 95% purity-90% recovery targets for postcombustion streams representative of wet flue gas from a coal-fired power plant (after SOx/NOx removal). The maximum productivity attained is 91.8 kg CO2 m−3 adsorber h−1 for 15% CO2, 82 % N2, and 3% H2O feed at 25 °C (i.e., 95% relative humidity) operated on a five-step cycle and regenerated at 150 °C.

Technical-economic evaluation of an energy-integrated temperature swing adsorption process for compressed air drying

The technical and economic performance of an energy-integrated temperature swing adsorption process was analyzed. The new process allows the dryer to recover the pressure energy of the compressed air used as a purge gas, and thereby achieving economically practical energy conservation. To understand the effects of the retrofit from the conventional process to the energy-integrated process on the dryer performance, the two processes were numerically studied. The operation parameters of the energy-integrated process were determined from a provided dryer by a design procedure, of which the purpose is to ensure that the two processes have comparable regeneration effects. In conclusion, the energy-integrated process reduces by about 37.5% of electricity consumption compared with the conventional process. The economic analysis shows that the incremental investment for the retrofit from the conventional process to the energy-integrated process is effective since the payback period is less than one year.

A rapid multi-objective optimization of pressure and temperature swing adsorption for CO2 capture based on simplified equilibrium model

• A new equilibrium model for PTSA cycle is developed for rapid optimization. • The equilibrium model is verified by 2-D dynamic model. • The equilibrium model is used to optimize the cycle rapidly and screen adsorbents. • Zeolite 13X-APG has the best exergy efficiency among twenty adsorbents. • The error of the equilibrium model is controlled to 0.1% by correction. CO 2 capture by adsorption is considered to be one of the powerful technologies to achieve carbon neutrality and alleviate global warming. However, adsorption technology is still limited by cycle performance such as energy cost, etc. at the present stage, and the optimization research of the technology deserves attention. But the development of optimization technology is limited by the large time of experiment and large calculation cost and simulation. In recent years, computational model based on equilibrium hypothesis has been used in rapid cycle optimization because of its relatively accurate calculation results and less computation. In this paper, a new equilibrium model was developed for a four-step pressure and temperature swing adsorption (PTSA) cycle for CO 2 capture, and it was verified by a complex model, i.e., 2-D dynamic model. Then, the parameters of PTSA cycle were optimized by using equilibrium model, and the relationship of cycle performance (purity, recovery and exergy efficiency) was analyzed. It is found that the number of optimal Pareto solutions is the largest when the adsorption temperature is 293 K (ambient temperature). There is a competitive relationship between recovery rate and exergy efficiency. Twenty adsorbents were screened according to their optimal circulation indexes, and Zeolite 13X-APG (ZEO_13X_APG) has the best exergy efficiency among them. Finally, a method to improve the optimization accuracy by correction was introduced, and the error of cycle performance was reduced to 0.1%.

Water adsorption and hydrothermal stability of CHA zeolites with different Si/Al ratios and compensating cations

Zeolites are well known crystalline aluminosilicates, which may be used in processes that take advantage of their molecular sieving effect, such as natural gas drying. They are often used in cyclic processes that swing pressure and/or temperature to perform adsorption and desorption steps. It is recognized that thermal stress may decrease process performance upon prolonged use. In this work, chabazite (CHA) zeolite with two different Si/Al ratios and compensating cations was investigated by thermally aging the samples using a laboratory-scale protocol. A Premature Aging Protocol – PAP was proposed that took into account the conditions which the adsorbent is exposed to in Temperature Swing Adsorption (TSA) process for natural gas drying. The sample was previously saturated with water and n-heptane vapors (as a reference hydrocarbon) followed by pressurization (30 bar) and heating (573 K) with a mixture of CO2 and CH4 (1:4, v/v). The Si/Al ratios of the CHA samples under study were 2 and 5 and the compensating cations were Na and K. Aged materials presented a lower CO2 and water vapor adsorption capacity with an increasing content of carbon in the bulk composition. The sample with higher Si/Al ratio (≈5) had a larger pore volume but adsorbed less water. Despite having the highest carbon content after aging and modest acidity, it was the most thermally stable sample, together with the sample containing potassium. Even with a lower Si/Al ratio (≈2), the presence of potassium provided the sample a protective effect against aging.

CO2 Separation from Flue Gases by Adsorption

This paper deals with gas separation by adsorption processes. The key objective is to investigate the adsorption suitability for Post-combustion Carbon Dioxide (CO2) Capture (PCC). Adsorption is a promising technology suitable for a high volume of diluted gas processing. Unlike commercialised amine-based absorption processes, adsorption seems to require less energy for sorbent regeneration and extends the sorbent lifetime. Two common industrial methods utilizing a difference in adsorption equilibrium of the gas components were investigated: 1) Pressure Swing Adsorption (PSA) including Vacuum Swing Adsorption (VSA), 2) Temperature Swing Adsorption (TSA). A comparison of their energy consumption, suitability for industrial use with consideration of Carbon Capture and Storage standards is evaluated. A complex mathematical model for the adsorption step of the fixed bed adsorber was proposed and solved by the structural programming. Three adsorbent materials: Mg-MOF-74, UTSA-16, and Zeolite 13X were evaluated based on their CO2 adsorption capacity, selectivity, and market availability. Zeolite 13X was further explored. As a benchmark case, a medium-sized natural gas cogeneration unit was used to study the potential of VSA unit. The lower limit of CO2 capture efficiency in simulations was 75 %. The results presented in this paper suggest that adsorption can be a feasible CO2 capture solution for a low-carbon emission power generation technologies. Optimal parameters for the adsorption step and column configuration are proposed.

Temperature swing adsorption for CO2 capture: Thermal design and management on adsorption bed with single-tube/three-tube internal heat exchanger

CO2 adsorption technology, especially temperature swing adsorption (TSA), is an important and effective method to reduce carbon dioxide emissions and achieve carbon neutrality. Considering the fact that adsorption bed is the most energy-intensive part in the TSA system, the thermal design and management towards internal heat exchanger (single-tube/three-tube) in adsorption bed is essential to improve energy efficiency. In this study, the self-coded TSA process including three steps (adsorption, desorption and cooling) is carried out using zeolite 13X-APG. Under the same surface area, heat transfer area, total amount of adsorbent, operation pressure and inlet flow rate, the thermal design schemes including inlet speed, porosity and adsorption/desorption temperature based on single-tube/three-tube heat exchanger in adsorption bed are discussed. The results show that the three-tube heat exchanger is superior to the single-tube heat exchanger in energy efficiency performance under the same conditions. With the increase of inlet speed and porosity, the COPCO2 (Coefficient of Performance of CO2 Capture) of the three-tube heat exchanger increased by 5.9% and 1.4%, respectively, and the specific energy consumption decreased by 8.5% and 5.4%, respectively. Decreasing of adsorption temperature, increasing of desorption temperature result in the improvement of the separation and energy-efficiency performance in adsorption bed. The findings are beneficial to optimize the geometric structure and operation strategy of the adsorption bed in TSA system.

BaTiO3-based thermistor hollow fibers prepared using a phase inversion spinning process for energy efficient gas sorption

Positive temperature coefficient of resistivity (PTCR) hollow fibers that exhibit self-regulating heating characteristics have potential applications in temperature-swing adsorption systems (TSA), such as CO2 recovery and drying of compressed air. La-doped BaTiO3 hollow fibers displaying a PTCR effect were produced by phase inverting a casting solution consisting of N-methly-2-Pyrrolidone, polymethyl methacrylate, polyvinylpyrrolidone, BaTiO3, TiO2, and La2O3 through a spinneret into a coagulating waterbath. This was followed by polymer debinding, high temperature sintering between 1350−1400 °C and annealing in air at 1175 °C to produce hollow fibers of the composition Ba0.9975La0.0025TiO3. Hydrothermal synthesis was implemented to deposit an adsorbent porous zeolite X layer within the hollow fiber lumen, which was confirmed by electron dispersive X-ray spectroscopy and CO2 adsorption at 0 °C. Hence, these materials can be applied to energy efficient TSA gas separation processes. The results are discussed in terms of hollow fiber microstructure, adsorption characteristics and electrical properties.

Improvement of the Oxygen Storage/Release Speed of YBaCo4O7+δ Synthesized by a Glycine-Complex Decomposition Method.

The present study explores the oxygen storage capacity of YBaCo4O7+δ prepared by a glycine-complex decomposition method. We reported for the first time that the YBaCo4O7+δ sample was successfully synthesized at such a low temperature of 800 °C by this method. The YBCO-800 N sample exhibited a faster oxygen absorption/desorption speed than that of high calcination temperature samples, and the time required for complete oxygen storage/release was 5 and 6 min at 360 °C, respectively. Moreover, the superior performance observed for this product in the temperature swing adsorption process makes it a promising candidate in oxygen production technologies. This research demonstrated that the glycine-complex decomposition method is an effective method for improving the oxygen storage property of YBaCo4O7+δ and provides a new insight into designing other novel oxygen storage materials.

Review on Carbon Capture in ICE Driven Transport

The transport sector powered by internal combustion engines (ICE) requires novel approaches to achieve near-zero CO2 emissions. In this direction, using CO2 capture and storage (CCS) systems onboard could be a good option. However, CO2 capture in mobile sources is currently challenging due to the operational and space requirements to install a CCS system onboard. This paper presents a systematic review of the CO2 capture in ICE driven transport to know the methods, techniques, and results of the different studies published so far. Subsequently, a case study of a CCS system working in an ICE is presented, where the energy and space needs are evaluated. The review reveals that the most suitable technique for CO2 capture is temperature swing adsorption (TSA). Moreover, the sorbents with better properties for this task are PPN-6-CH2-DETA and MOF-74-Mg. Finally, it shows that it is necessary to supply the energy demand of the CCS system and the option is to take advantage of the waste heat in the flue gas. The case study shows that it is possible to have a carbon capture rate above 68% without affecting engine performance. It was also found that the total volume required by the CCS system and fuel tank is 3.75 times smaller than buses operating with hydrogen fuel cells. According to the review and the case study, it is possible to run a CCS system in the maritime sector and road freight transport.

Kinetics and Thermodynamic Modeling for CO2 Capture Using NiO Supported Activated Carbon by Temperature Swing Adsorption

Solid sorbent from functionalized activated carbon (AC) could enhance the adsorption capacity in CO2 capture. This study emphasizes cyclic CO2 capture using NiO functionalized AC. Different loadings of NiO impregnated on AC were synthesized. This work showed that the most efficient adsorbent of 0.05NiO/AC exhibits an adsorption capacity of 55.464 mg/g at the adsorption temperature of 30 °C by using the temperature swing adsorption method. A slight loss of adsorption capacity at 0.28 % for a five cycles CO2 capture indicated consistency potential for large scales application. The adsorbent exhibited a slightly lower surface area compared to AC, but the presence of NiO improved the adsorption capacity by chemisorption phenomena. The NiO acts as the basic site for CO2 capture. Meanwhile, AC as support could increase the surface area of active sites and reduce the sintering effect of the NiO. It was found that various adsorption temperatures had a good correlation with the pseudo-second-order kinetic model. The magnitude of the sorption process was evaluated by the activation energy of 48.09 kJ/mol, which implies a chemisorption process at various adsorption temperatures. Thermodynamic studies explained the CO2 adsorption process for this study was found to be a spontaneous and endothermic process.

Carbon Dioxide Capture Using Sorbent-Loaded Hollow-Fiber Modules for Coal-Fired Power Plants

Abstract The impact of post-combustion carbon dioxide capture on the performance of a power plant is evaluated. A model of a coal power plant with post-combustion temperature swing adsorption (TSA) CO2 capture using sorbent-loaded hollow fibers is presented. The resulting performance and cost of carbon capture are compared with those of other adsorption-based technologies. A parametric analysis of the performance of the power plant with respect to key parameters in the hollow fiber module operation is presented. It is found that electrical energy consumption for the compression of CO2 is a major parasitic load (PL) common to all absorption technologies and accounts for almost half of the total parasitic load. The effect of source temperature, flue gas (FG) fan, and coupling fluid pump flowrates on overall system performance is presented. The impacts of different carbon capture technologies on the same coal-fired power plant are compared. Hollow fiber modules had the lowest parasitic load on the power plant, followed by KS-2 based carbon capture.

Postcombustion CO2 Capture: A Comparative Techno-Economic Assessment of Three Technologies Using a Solvent, an Adsorbent, and a Membrane

This work compares three postcombustion CO2 capture processes based on mature technologies for CO2 separation, namely, (i) absorption using an aqueous piperazine solution, (ii) adsorption using Zeolite 13X in conventional fixed beds (either vacuum swing adsorption or temperature swing adsorption), and (iii) multistage membrane separation using a polymeric material (with CO2/N2 selectivity of 50 and permeability for CO2 of 1700 GPU). All three capture plants are assumed to be retrofitted to a generic industrial CO2-emitting source with 12% CO2 v/v (with 95% relative humidity at the inlet temperature and pressure of 30 °C and 1.3 bar, respectively) to deliver CO2 at 96% purity. In the cases of adsorption and membranes, the flue gas is dried before feeding it to the CO2 capture unit. In a first step, the capture processes (i.e., components and design parameters) are optimized based on their technical performance, defined through process exergy requirement and plant productivity; exergy–productivity Pareto fronts are computed for varying CO2 recovery rates. Second, the economic performance of the processes is assessed through a cost analysis. Estimates of CO2 capture costs are provided for each process as a function of the plant size and CO2 recovery rate. The comparative assessment shows that, although the adsorption- and membrane-based processes analyzed may become cost competitive at the small scale (i.e., below sizes of 100 tons of flue gas processed per day) and low recovery rates (i.e., below ca. 40%), the absorption-based process considered is the most cost-effective option at most plant sizes and recovery rates.