Carbonation kinetics of fly‐ash‐modified calcium‐based sorbents for CO<sub>2</sub> capture

Chen, Huichao; Wang, Fang; Zhao, Changsui; Duan, Lunbo

doi:10.1002/ghg.1739

Cited by 7 publications

(7 citation statements)

References 37 publications

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“…Several ways of capturing carbon in coal‐fired power plants have been proposed, such as post‐combustion capture, pre‐combustion capture, and oxy‐combustion . As one of the post‐combustion methods, the calcium looping (CaL) technique is promising because of the availability of relatively abundant and cheap calcium‐based sorbents, and its high theoretical sorption capacity, i.e., 0.786g CO 2 /g CaO . However, it also faces a challenge in that the CO 2 uptake capacity of calcium‐based sorbent decreases with increasing CaL cycles .…”

Section: Introductionmentioning

confidence: 99%

Explaining steam‐enhanced carbonation of CaO based on first principles

et al. 2018

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Calcium-based sorbents have been regarded as effective agents for capturing CO 2 from industrial flue gas. Recent studies have shown that steam can enhance the carbonation performance of calcium-based sorbents. In this paper, a CaO (001) surface was made to investigate the micro-level mechanism of steam-enhanced carbonation based on first principles calculations. Charge transfer and bond population were calculated to evaluate an interaction effect between adsorbates and the CaO (001) surface. Individual adsorption of CO 2 and H 2 O was compared with binary adsorption and co-adsorption of the two molecules on the CaO (001) surface, based on dispersion-corrected density functional theory (DFT-D) calculations. First, the predicted adsorption energies suggest the O-top site is the best site. It forms carbonate-like structure and hydroxyl-like structure for the individual adsorption of CO 2 and H 2 O. Binary adsorption calculations indicate that H 2 O is more easily adsorbed by the CaO (001) surface than CO 2 . The adsorption of H 2 O and CO 2 adsorption are promoted in comparison with their individual adsorption on the CaO (001) surface. Moreover, the analysis of adsorption energies and partial density of states (PDOS) suggests that a H 2 O-CaO (001) surface (CaO (001) surface that has already adsorbed H 2 O) is more reactive than the clean CaO (001) surface for CO 2 adsorption, which further supports the idea that the steam-enhanced mechanism is an Eley-Rideal (E-R) mechanism, which means H 2 O is adsorbed on the CaO surface, and then CO 2 is adsorbed. C

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Section: Introductionmentioning

confidence: 99%

Explaining steam‐enhanced carbonation of CaO based on first principles

et al. 2018

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“…(b) and (c), a shift to the highest binding energy of Ca 2p and O 1s in C‐Mn‐CaO was found, which was not observed in the original CaO. It means that it was easier for the Ca atom and O atom in C‐Mn‐CaO to give electrons to CO 2 than the original CaO, which assisted the fast formation of CO 3 . The doping of Mn in CaO was beneficial to the electron transport from CaO to CO 2 , which accelerated the carbonation rates of CaO.…”

Section: Resultsmentioning

confidence: 93%

“…Natural calcium‐based sorbents like limestone, dolomite, and some calcium‐based industrial wastes like carbide slag, are used to capture CO 2 during the calcium looping process. However, the decay in the CO 2 capture capacities of calcium‐based sorbents with the number of carbonation / calcination cycles, resulting from sintering, is the major problem that limits CO 2 capture efficiency and the large‐scale industrial application of calcium looping . Attempts have been made to improve the CO 2 capture capacities and the sintering resistance of calcium‐based sorbents during multiple cycles.…”

Section: Introductionmentioning

confidence: 99%

A study of the synergistic effects of Mn/steam on CO₂ capture performance of CaO by experiment and DFT calculation

Wan

et al. 2019

Greenhouse Gases

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Novel Mn‐doped CaO was prepared by the combustion method. The CO2 capture performance of Mn‐doped CaO, carbonated in the presence of steam and under severe calcination conditions (950°C and 70% CO2/30% N2) during calcium looping cycles, was investigated in a dual fixed‐bed reactor. The intercoupling effects of Mn and steam on CO2 capture by CaO were also studied. Doping of Mn in CaO by the combustion method greatly improved the CO2 capture capacity of CaO. The carbonation conversions of Mn‐doped CaO increased with increasing steam concentration from 0 to 15%. When the molar ratio of Mn/Ca was 0.75 : 100, Mn‐doped CaO achieved the highest CO2 capture capacity. Under severe calcination conditions, the carbonation conversion of Mn‐doped CaO, where the molar ratio of Mn to Ca = 0.75 : 100 in the presence of 15% steam, was about 0.4 after ten cycles (carbonation for 5 min at 650°C under 15% CO2/15% steam/N2), which was 4.38 times as high as that of the original CaO in the absence of steam. The cyclic CO2 capture capacities of CaO were improved by Mn and steam. Synergistic enhancement effects of Mn and steam on the CO2 capture capacities of CaO were also found. The effect of steam on the carbonation conversion of Mn‐doped CaO was stronger than that of the original CaO. Mn in the presence of steam showed a more positive effect on CO2 capture by CaO. X‐ray photoelectron spectroscopy analysis showed that doping of Mn in CaO enhanced the transport of electrons in the carbonation of CaO, which helped to increase the carbonation rate. When steam was present in the carbonation, Mn‐doped CaO possessed a more porous structure and smaller CaO grains than the original CaO during the cycles. Simulation calculations using periodic density functional theory (DFT) showed that CO2 molecules were easier to absorb on CaO owing to the doping of Mn and the presence of steam. The synergistic enhancement effects of Mn and steam on CO2 captured the performance of CaO. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

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“…The decomposition of CaCO 3 , i.e., calcination reaction, is a highly endothermic process (eq ), which requires high temperatures provided by the oxy-fuel combustion of fuels . The calcination temperature is very dependent upon the atmosphere used during the calcination process.…”

Section: Fundamental Understanding Of the Cal Processmentioning

confidence: 99%

“…Various research work has been conducted on naturally occurring CaO-based sorbents, mainly including limestone, , dolomite, , and other natural materials, such as eggshells, , seashells, , lime mud, − and manganocalcite mineral, to evaluate their CO 2 capture performance for the potential large-scale industrial applications. However, the rapid decline in CO 2 capture performance has been widely reported for these natural materials . Thus, different activation strategies have been attempted to prevent and/or alleviate the rapid reactivity decay of these naturally occurring CaO-based sorbents.…”

Section: Improvements Of Naturally Occurring Cao-based Sorbentsmentioning

confidence: 99%

Review on the Development of Sorbents for Calcium Looping

2020

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The calcium looping (CaL) process is a promising CO 2 capture technology, which uses CaO-based sorbents by employing a reversible reaction between CaO and CO 2 , generally named carbonation and calcination for each direction of the reaction. Although CaO-based sorbents possess many advantages, including wide availability, relatively low cost, and high theoretical CO 2 uptake (∼0.786 g of CO 2 /g of CaO), it mainly suffers from a rapid decline in CO 2 capture performance during cyclic operation, which has remained an urgent issue required to be addressed for industrial applications of the CaL process. Extensive studies have been conducted thus far, attempting to prevent and/or alleviate the rapid performance decay of the sorbents. Thus, this paper reviews the recent development of the CaL process worldwide with an emphasis on its development in China, mainly focusing on the advancement in the design and reinforcement of CaO-based sorbents. These activation strategies mainly include doping, chemical pretreatment, incorporation of supports with high Tammann temperatures, and structural modification, which do enhance the cyclic performance of the sorbents. However, some challenges still exist in the development of the CaO-based sorbents, such as the cost of the synthesis route, the scale-up pathways of the sorbents, the assessment of cyclic performance under mild conditions, and the ignorance of mechanical strength and attrition resistance of the sorbents. Therefore, life cycle assessment together with techno-economic analysis is essential when synthesizing CaO-based sorbents. In addition, more work should be conducted under industrially relevant conditions in fluidized bed reactors and even pilot-scale reactors, which are much closer to industrial situations. In this case, mechanical strength and attrition resistance are also assessed during cyclic operation.

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Carbonation kinetics of fly‐ash‐modified calcium‐based sorbents for CO₂ capture

Cited by 7 publications

References 37 publications

Explaining steam‐enhanced carbonation of CaO based on first principles

Explaining steam‐enhanced carbonation of CaO based on first principles

A study of the synergistic effects of Mn/steam on CO₂ capture performance of CaO by experiment and DFT calculation

Review on the Development of Sorbents for Calcium Looping

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Carbonation kinetics of fly‐ash‐modified calcium‐based sorbents for CO2 capture

Cited by 7 publications

References 37 publications

Explaining steam‐enhanced carbonation of CaO based on first principles

Explaining steam‐enhanced carbonation of CaO based on first principles

A study of the synergistic effects of Mn/steam on CO2 capture performance of CaO by experiment and DFT calculation

Review on the Development of Sorbents for Calcium Looping

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Carbonation kinetics of fly‐ash‐modified calcium‐based sorbents for CO₂ capture

A study of the synergistic effects of Mn/steam on CO₂ capture performance of CaO by experiment and DFT calculation