CO2 Capture Energy Research Articles

Optimisation of an Integrated System: Combined Heat and Power Plant with CO2 Capture and Solar Thermal Energy

This paper aims to evaluate different design configurations of a combined heat and power (CHP) plant with post-combustion CO2 capture. Three cases are involved in this study: case 1 consists of three trains and each train has a configuration of one gas turbine with a heat recovery steam generator (HRSG); case 2 consists of three trains and one steam turbine; and case 3 consists of only two trains. The third case presented the highest CHP efficiency of 72.86% with 511.8 MW net power generation. After selecting the optimum configuration, a parabolic-trough collector (PTC) was incorporated to generate additional saturated steam at 3.5 bar for the capture plant, adding greater flexibility to the CHP because more steam was available. In addition, the efficiency of the cycle increased from 72.86% to 80.18%. Although case 2 presented lower efficiency than case 3, it has a steam turbine which brings the possibility of increasing the amount of electricity instead of steam production. When the PTC was incorporated in case 2, the power generated in the steam turbine increased from 23.22 MW to 52.6 MW, and the net efficiency of the cycle from 65.4% to 68.21%.

The potential of direct air capture using adsorbents in cold climates.

Global warming threatens the entire planet, and solutions such as direct air capture (DAC) can be used to meet net-zero goals and go beyond. This study investigates using DAC in a 5-step temperature vacuum swing adsorption (TVSA) cycle with adsorbents' Li-X and Na-X, readily available industrial zeolites, to capture and concentrate CO2 from air in cold climates. From this study, we report that Na-X in cold conditions has the highest known CO2 adsorption capacity in air of 2.54mmol/g. This combined with Na-X's low CO2 heat of adsorption, and fast uptake-rate in comparison to other benchmark materials, allowed for Na-X operating in cold conditions to have the lowest reported DAC operating energy of 1.1 MWh/tonCO2. These findings from this study show the promise of this process in cold climates of Canada, Alaska, Greenland, and Antarctica to be part of the solution to global warming.

Photoinduced phase transitions in nanogel particles for reversible CO2 capture

Solar energy has been utilized to strip CO2 for saving the CO2 capture energy consumption. However, a large temperature swing is necessary for higher regeneration efficiency, which also will result in a serious materials degradation. Herein, we report a photo triggered phase transition strategy for reversible capture CO2 using amine containing nanogel particles-based solvents with a small temperature swing. The composite absorbents were prepared by combing N-[3-(dimethylamino)propyl]methacrylamide containing nanogel particles with polydopamine. The phenomenon of photoinduced phase transition was observed in both nanogel particles-based solvents and the composite absorbents. Although the nanogel particles can release most of CO2 undergo a light irradiation, the composite absorbents present a more faster desorption rate than the former, which can be explained by an enhanced light absorbability and photothermal conversion efficiency of the latter. An average CO2 regeneration efficiency can reach up to 92.45% in five CO2 uptake and release cycles, indicating that the photo triggered phase transition can be used to develop energy efficient CO2 capture technology.

EMmim][NTf2 ]-a Novel Ionic Liquid (IL) in Catalytic CO2 Capture and ILs' Applications.

Ionic liquids (ILs) have been used for carbon dioxide (CO2 ) capture, however, which have never been used as catalysts to accelerate CO2 capture. The record is broken by a uniquely designed IL, [EMmim][NTf2 ]. The IL can universally catalyze both CO2 sorption and desorption of all the chemisorption-based technologies. As demonstrated in monoethanolamine (MEA) based CO2 capture, even with the addition of only 2000ppm IL catalyst, the rate of CO2 desorption-the key to reducing the overall CO2 capture energy consumption or breaking the bottleneck of the state-of-the-art technologies and Paris Agreement implementation-can be increased by 791% at 85°C, which makes use of low-temperature waste heat and avoids secondary pollution during CO2 capture feasible. Furthermore, the catalytic CO2 capture mechanism is experimentally and theoretically revealed.

Evaluation and screening of porous materials containing fluorine for carbon dioxide capture and separation

There is a significant challenge to discover porous materials that can effectively capture and separate CO2 from natural gas, refining gas, and flue gas, which has attracted attention in dealing with climate warming and energy purification. Recently, hybrid microporous materials with narrow pores and containing fluorine have been rapidly used in gas separation based on physisorption. In this contribution, molecular simulations combined with high-throughput calculations were performed to calculate structural parameters and performance evaluation metrics of 1015 promising adsorbents to rank and screen out the top candidates for CO2/CH4, CO2/H2 and CO2/N2 separation. To the best of our knowledge, this is the first time to unlock this kind of fluorinated material database in CO2 separation, in which statistical information indicates that a large number of interpenetrating structures lead to 64% of ultra-microporous materials and the number of particles per unit volume of fluorine we defined also has a positive effect on the heat of adsorption of CO2. The structural performance relationship reveals a clear picture of strong CO2 capture but poor energy gas (CH4 and H2) storage. The mathematical model established from the geometry and energy descriptors has a strong correlation with the mixture adsorption selectivity in CO2/N2 separation, and the ideal selectivity can be applied to save computing resources in CO2/H2 separation. Cadmium and vanadium with high frequency may represent the new characteristics of the next generation adsorbent for capturing CO2, among the 18 high-performance materials selected according to the adsorption performance score and mixture adsorption selectivity. The centroid density distribution and radial distribution function manifest that CO2 is preferentially close to fluorine atoms and metal atoms. Here, we established an online high-throughput calculation code (https://github.com/oddthinker/HTCS) for adsorption and separation. All of this will provide guidelines for experimental synthesis and large-scale screening of target materials.

Sustainability Enhancement of Fossil-Fueled Power Plants by Optimal Design and Operation of Membrane-Based CO2 Capture Process

Fossil-fueled power plants are a major source of carbon dioxide (CO2) emission and the membrane process is a promising technology for CO2 removal and mitigation. This study aims to develop optimal membrane-based carbon capture systems to enhance the sustainability of fossil-fuel power plants by reducing their energy consumption and operating costs. The multi-stage membrane process is numerically modeled using Aspen Custom Modeler based on the solution-diffusion mechanism and then the effects of important operating and design parameters are investigated. Multi-objective process optimization is then carried out by linking Aspen Plus with MATLAB and using an evolutionary technique to determine optimal operating and design conditions. The results show that, as the CO2 concentration in the feed gas increases, the CO2 capture cost significantly decreases and CO2 removal is enhanced, although the process energy demand slightly increases. The best possible trade-offs between objective functions are reported and analyzed, which confirm the considerable potential for improving the sustainability of the process. The CO2 capture cost and energy penalty of the process is as low as 13.1 $/tCO2 and 10% at optimal design and operating conditions. This study provides valuable insight into membrane separation and can be used by decision-makers for the sustainable improvement of fossil-fueled power plants.

Chemical looping technology – a manifestation of a novel fluidization and fluid-particle system for CO2 capture and clean energy conversions

Chemical looping is broadly defined to represent processes that use chemical intermediates to decompose a reaction into two or more sub-reaction steps. Metal oxides are the typical chemical intermediates used for the chemical looping reactions although other metal derivatives are also used. Based on its intended applications, chemical looping encompasses calcium looping for CO 2 capture and redox looping for clean energy conversion applications. The redox looping has a longstanding history and has been demonstrated at multiple scales under various operating conditions since its conceptual inception about 120 years ago. Even with such extensive and prolonged efforts, redox looping is yet to be realized sustainably at a commercial level, while the calcium looping has been demonstrated for commercial applications. With growing concerns of climate change due to emissions of industrial greenhouse gases, efforts in developing redox looping processes as a promising fossil energy conversion technology with CO 2 emission control have been invigorated since the beginning of the 21st century. Metal oxide reaction engineering and particle science and technology have been the two enabling technical thrust areas, pivotal to advance the chemical looping concept to industrial practice. This article highlights some salient features of the chemical looping processes including a description of their historical development and illustration of the material screening and synthesis of oxygen carrier particles along with the representative process operational behavior. Recognizing that the configuration of chemical looping systems in their key operational scheme is established on the framework of circulating fluidized bed (CFB) systems, this article emphasizes the relevant characteristics of fluidization and fluid-particle systems with which the chemical looping technology is conducted. Both the fundamental and applied aspects of chemical looping processes and their associated CFB operation are discussed. • Chemical looping has garnered significant attention due to its inherent advantages. • The development of processes has been over 120 years. • Material screening and synthesis of oxygen carrier is the core. • System is related to many characteristics of fluidization and fluid-particle topic. • Fundamental and applied aspects of chemical looping processes are discussed.

Front Cover: CO2 Separation by Imide/Imine Organic Cages (Chem. Eur. J. 49/2022)

CO2 capture and clean energy production technologies are stirring increasing interest due to the visible effects of global warming on our planet. In the background is a picture of a small lake in Lombardy, Italy, as it appeared in 2018. Novel imide/imine cages have shown promising results in the selective separation of CO2 from N2 and CH4 under vacuum swing adsorption conditions. The cages have also been successfully tested as fillers in mixed-matrix membranes. More information can be found in the Research Article by J. C. Jansen, M. Carta, V. Amendola et al. (DOI: 10.1002/chem.202201631).

Special Issue “CO2 Capture and Renewable Energy”

This book contains the successful submissions [...]

Methanol biotransformation toward high-level production of fatty acid derivatives by engineering the industrial yeast Pichia pastoris.

Methanol-based biorefinery is a promising strategy to achieve carbon neutrality goals by linking CO2 capture and solar energy storage. As a typical methylotroph, Pichia pastoris shows great potential in methanol biotransformation. However, challenges still remain in engineering methanol metabolism for chemical overproduction. Here, we present the global rewiring of the central metabolism for efficient production of free fatty acids (FFAs; 23.4 g/L) from methanol, with an enhanced supply of precursors and cofactors, as well as decreased accumulation of formaldehyde. Finally, metabolic transforming of the fatty acid cell factory enabled overproduction of fatty alcohols (2.0 g/L) from methanol. This study demonstrated that global metabolic rewiring released the great potential of P. pastoris for methanol biotransformation toward chemical overproduction.

Development of Uniform Porous Carbons From Polycarbazole Phthalonitriles as Durable CO2 Adsorbent and Supercapacitor Electrodes.

Advances in new porous materials have recognized great consideration in CO2 capture and electrochemical energy storage (EES) applications. In this study, we reported a synthesis of two nitrogen-enriched KOH-activated porous carbons prepared from polycarbazole phthalonitrile networks through direct pyrolysis protocol. The highest specific surface area of the carbon material prepared by pyrolysis of p-4CzPN polymer reaches 1,279 m2 g−1. Due to the highly rigid and reticular structure of the precursor, the obtained c-4CzPN–KOH carbon material exhibits high surface area, uniform porosity, and shows excellent CO2 capture performance of 19.5 wt% at 0°C. Moreover, the attained porous carbon c-4CzPN–KOH showed high energy storage capacities of up to 451 F g−1 in aqueous electrolytes containing 6.0 M KOH at a current density of 1 A g-1. The prepared carbon material also exhibits excellent charge/discharge cycle stability and retains 95.9% capacity after 2000 cycles, indicating promising electrode materials for supercapacitors.

Promoting effects of Li3PO4 and CaCO3 on the intermediate-temperature CO2 adsorption over molten NaNO3-promoted MgO-based sorbents

Molten nitrate-promoted MgO-based sorbents represent a potential class of materials for CO2 capture at intermediate temperatures. However, their poor stability under harsh but realistic regeneration conditions (e.g., at high temperatures in pure CO2) is a challenge for the application of CO2 capture. In this work, a series of NaNO3 and/or Li3PO4 promoted MgO and MgO-CaCO3 sorbents were prepared, characterized, and evaluated. The results showed that the NaNO3-Li3PO4 promoted MgO-CaCO3 sorbents had high CO2 adsorption performance in terms of rate, capacity and stability, which was attributed to the promoting effect of Li3PO4 and CaCO3. Li3PO4 can enhance the surface adsorption of CO2 by providing some extra moderate basic sites, while CaCO3 can accelerate the carbonation reaction of bulk MgO via the formation of CaMg(CO3)2. In addition, Li3PO4 can hinder the sintering of sorbent particles, and consequently improve the stability of the sorbent. The optimized sorbent had a stable CO2 uptake of 0.12 (or 0.26) gCO2/gsorbent when 30% (or pure) CO2 was used at the adsorption stage in long-term cyclic operation (desorption at 500 °C in pure CO2 for both cases), showing promising applications in intermediate-temperature CO2 capture and thermochemical energy storage.

Fabrication of Hollow Nanocones Membrane with an Extraordinary Surface Area as CO2 Sucker.

Recently, more and more attention has been paid to the development of eco-friendly solid sorbents that are cost-effective, noncorrosive, have a high gas capacity, and have low renewable energy for CO2 capture. Here, we claimed the fabrication of a three-dimensional (3D) film of hollow nanocones with a large surface area (949.5 m2/g), a large contact angle of 136.3°, and high surface energy. The synthetic technique is based on an electrochemical polymerization process followed by a novel and simple strategy for pulling off the formed layers as a membrane. Although the polymer-coated substrates were reported previously, the membrane formation has not been reported elsewhere. The detachable capability of the manufactured layer as a membrane braked the previous boundaries and allows the membrane’s uses in a wide range of applications. This 3D hollow nanocones membrane offer advantages over conventional ones in that they combine a π-electron-rich (aromatic ring), hydrophobicity, a large surface area, multiple amino groups, and a large pore volume. These substantial features are vital for CO2 capturing and storage. Furthermore, the hydrophobicity characteristic and application of the formed polymer as a CO2 sucker were investigated. These results demonstrated the potential of the synthesized 3D hollow polymer to be used for CO2 capturing with a gas capacity of about 68 mg/g and regeneration ability without the need for heat up.

Energy and Cost-Efficient Temperature Vacuum Swing Adsorption Processes for CO2 Capture in a Rotating Column Reactor

Energy and Cost-Efficient Temperature Vacuum Swing Adsorption Processes for CO2 Capture in a Rotating Column Reactor

Design and Costing of an ION Clean Energy CO2 Capture Plant Retrofitted to a 700 MW Coal-fired Power Station Including Local Biomass Co-combustion for Near Zero-Emissions

Design and Costing of an ION Clean Energy CO2 Capture Plant Retrofitted to a 700 MW Coal-fired Power Station Including Local Biomass Co-combustion for Near Zero-Emissions

A steric hindrance alleviation strategy to enhance the photo-switching efficiency of azobenzene functionalized metal–organic frameworks toward tailorable carbon dioxide capture

A steric hindrance alleviated photo switching metal–organic framework reported for low energy CO2 capture and release.

Design and Costing of an ION Clean Energy CO2 Capture Plant Retrofitted to an 857 MW Natural Gas Combined Cycle Power Station

Design and Costing of an ION Clean Energy CO2 Capture Plant Retrofitted to an 857 MW Natural Gas Combined Cycle Power Station

Microporous Carbon and Carbon/Metal Composite Materials Derived from Bio-Benzoxazine-Linked Precursor for CO2 Capture and Energy Storage Applications.

There is currently a pursuit of synthetic approaches for designing porous carbon materials with selective CO2 capture and/or excellent energy storage performance that significantly impacts the environment and the sustainable development of circular economy. In this study we prepared a new bio-based benzoxazine (AP-BZ) in high yield through Mannich condensation of apigenin, a naturally occurring phenol, with 4-bromoaniline and paraformaldehyde. We then prepared a PA-BZ porous organic polymer (POP) through Sonogashira coupling of AP-BZ with 1,3,6,8-tetraethynylpyrene (P-T) in the presence of Pd(PPh3)4. In situ Fourier transform infrared spectroscopy and differential scanning calorimetry revealed details of the thermal polymerization of the oxazine rings in the AP-BZ monomer and in the PA-BZ POP. Next, we prepared a microporous carbon/metal composite (PCMC) in three steps: Sonogashira coupling of AP-BZ with P-T in the presence of a zeolitic imidazolate framework (ZIF-67) as a directing hard template, affording a PA-BZ POP/ZIF-67 composite; etching in acetic acid; and pyrolysis of the resulting PA-BZ POP/metal composite at 500 °C. Powder X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and Brunauer–Emmett–Teller (BET) measurements revealed the properties of the as-prepared PCMC. The PCMC material exhibited outstanding thermal stability (Td10 = 660 °C and char yield = 75 wt%), a high BET surface area (1110 m2 g–1), high CO2 adsorption (5.40 mmol g–1 at 273 K), excellent capacitance (735 F g–1), and a capacitance retention of up to 95% after 2000 galvanostatic charge–discharge (GCD) cycles; these characteristics were excellent when compared with those of the corresponding microporous carbon (MPC) prepared through pyrolysis of the PA-BZ POP precursors with a ZIF-67 template at 500 °C.

Can Charge-Modulated Metal-Organic Frameworks Achieve High-Performance CO2 Capture and Separation over H2 , N2 , and CH4 ?

CO2 capture and separation by using charge-modulated adsorbent materials is a promising strategy to reduce CO2 emissions. Herein, three TM-HAB (TM=Co, Ni, and Cu; HAB=hexa-aminobenzene) metal-organic frameworks (MOFs) were evaluated as charge-modulated CO2 capture and separation materials by using density functional theory and grand canonical Monte Carlo simulations. The results showed that each TM-HAB presented a high electrical conductivity and structural stability when injecting charges. The CO2 adsorption energy increased from 0.211 to 2.091 eV on Co-HAB, 0.262 to 2.119 eV on Ni-HAB, and 0.904 to 2.803 eV on Cu-HAB, respectively, with the increase in charge state from 0.0 to 3.0 e- . Co-HAB and Ni-HAB were better charge-modulated CO2 capture materials with less structure deformation based on energy decomposition analyses. The kinetic process demonstrated that considerably low energy consumptions of 0.911 and 1.589 GJ ton-1 CO2 were observed for a complete adsorption-desorption cycle on Co-HAB and Ni-HAB. All charged MOFs, especially Co-HAB and Ni-HAB, exhibited higher CO2 adsorption energies and adsorption capacities than those of H2 , N2 , and CH4 , thereby exhibiting high CO2 selectivities. Interaction analysis confirmed that the injecting charges had a more pronounced enhancement in the coulombic interactions between CO2 and MOFs. The results of this work highlight Co-HAB and Ni-HAB as promising charge-modulated CO2 capture and separation materials with controllable CO2 capture, high selectivity, and low energy consumption.

Electroreduction of low concentration CO2 at atomically dispersed Ni-N-C catalysts with nanoconfined ionic liquids

Most studies on electrochemical CO2 reduction reaction use pure CO2, which requires extra energy for CO2 capture and enrichment from atmosphere. Herein, nanoconfined ionic liquids are introduced into porous atomically dispersed nickel-nitrogen-carbon (Ni-N-C) catalysts to enrich local CO2 concentration and increase the CO2RR kinetics. A series of high-CO2-solubility ionic liquids (ILs) were impregnated into the pores of the columnar Ni-N-C catalyst to alter the CO2-Ni sites interactions and create a solid/liquid interface with high CO2 concentration. The optimal Ni-N-C/[Bmim][PF6] composite outperforms the Ni-N-C catalyst for pure CO2 electroreduction with a maximum FECO of 99.6% and 2.7-fold larger jCO. The high solubility of CO2 in ILs compared to aqueous electrolyte enables direct electrolysis of CO2 at low concentrations. When fed with 5–10% (v/v) CO2, the Ni-N-C/[Bmim][PF6] composite exhibited up to 1.5-fold higher FECO and a 68% increase of jCO, in comparison to Ni-N-C, and robust stability over 30 h.