The decrease of carbonation efficiency of CaO along calcination–carbonation cycles: Experiments and modelling

Bouquet, Eric; Leyssens, Gontrand; Schönnenbeck, Cornélius; Gilot, P.

doi:10.1016/j.ces.2009.01.045

Cited by 59 publications

(40 citation statements)

References 21 publications

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“…In particular, when particle size is sufficiently small, the whole process finally turns to chemical-controlled stage. [35][36][37] As shown in Figure 11, during the whole adsorption/desorption cycles, cycle curves did not perform notably different from one another. According to the criterion of dividing the fastand slow-reaction stages, which is proposed by Wu and Lan, 38 a dividing line of the two reaction stages is marked in Figure 11.…”

Section: With Etoh Solution Treatmentmentioning

confidence: 79%

Enhanced CO₂ adsorption capacity and stability using CaO‐based adsorbents treated by hydration

et al. 2013

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The synthesis of highly efficient CaO-based sorbents using Ca(Ac) 2 as a precursor and ethanol as a modification agent for CO 2 capture is described. This adsorbent has several characteristics such as large surface area and pore volume and small particle size. The influence of ratio of ethanol and water on CO 2 adsorption capacity was evaluated considering that the ethanol concentration could affect the pore structure of sorbents. The results showed that CaO modified by ethanol solution had a higher carbonization and better stability. Particularly, when the volume ratio of ethanol and water was 3, a performance of adsorption capacity of 74% and conversion of 94% was observed. CaO modified by ethanol solution had a superior performance due to the decrease of grain size and the formation of loose porous structure. The influence of steam on stability of adsorbents at high temperatures was examined, and it was found that with the existence of steam diffusion, the capacity of the sorbent could remain at a higher level and the stability was evidently improved. After 18 cycles of adsorption/desorption process, the capacity remained as high as 65%. It was proposed that dynamic and cyclic steam injection was favorable for preventing the sintering of sorbents and facilitating the diffusion of CO 2 .

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Section: With Etoh Solution Treatmentmentioning

confidence: 79%

Enhanced CO₂ adsorption capacity and stability using CaO‐based adsorbents treated by hydration

et al. 2013

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“…Even if several studies [15][16][17][18][19] have been done in order to explain the decrease of the maximum extent of carbonation along carbonation/decarbonation cycles, comprehensive studies of the R1 equation remain quite rare.…”

Section: Introductionmentioning

confidence: 99%

“…Bouquet et al [15] used directly this shrinking core model and Bhatia et al [21] applied the random pore model. Both works allowed to represent experimental data for the rapid initial stage of the reaction but the kinetic slowing down and the slow second stage cannot be modeled correctly.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the kinetic slowing down during carbonation of CaO by CO2

Rouchon

Favergeon

Pijolat

2013

J Therm Anal Calorim

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To cite this version:Lydie Rouchon, LoÏc Favergeon, Michèle Pijolat. Analysis of the kinetic slowing down during carbonation of CaO Keywords:Carbonation, Calcium oxide, Kinetics, Porosity, TG Abstract:In order to improve the capture capacity of CaO-based sorbents, it appears important to understand the mechanism of calcium oxide carbonation and to get details on kinetic law controlling the reaction, which has not been really studied up to now. To investigate this mechanism, CaO carbonation kinetics was followed by means of thermogravimetric analysis (TG) on divided materials, of textural and morphological characterizations and of an original kinetic approach devoted to look for the rate-determining step controlling the reaction rate.In order to better describe the reaction mechanism, the influence of intensive variables such as carbonation temperature and CO 2 partial pressure were investigated. TG curves obtained under isothermal (450-650°C) and isobaric conditions (2-30 kPa) show a strong slowing down of the conversion leading to incomplete reaction. This slowing down and the fractional conversion at which it appears depend on carbonation temperature and CO 2 partial pressure.To explain these results, particular attention has been paid to the evolution the textural properties of the solid during processing. The solid powder consists of porous aggregates in which the porosity changes along the reaction due to the difference in the molar volumes of CaO and CaCO 3 .Temperature jumps during TG experiments have put in evidence a complex kinetic behavior since three distinct domains must be distinguished, over all the conversion range, whatever 32 2 the temperature and CO 2 pressure could be. The discussion of the results emphasizes the role of the porosity on the kinetic non-Arrhenius behavior observed in the second domain.

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“…Bathia et al [1], Silaban et al [2] and Bouquet et al [3] explained this shape by a decrease in porosity and Abanades et al [4] by the formation of a layer of CaCO 3 covering CaO aggregates. The effects of the experimental conditions on CaO carbonation were also studied.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, Sun et al [8] applied this model to only a short linear part. Bouquet et al [3] also used this model and explained the first step of carbonation; -at the aggregate scale, the gradient of CO 2 partial pressure inside aggregate pores and the closing of pores were considered. So, Bathia et al [1] applied the random pore model and Sun et al [9] performed a coupling between random pore model and grain model with a discrete pore size distribution.…”

Section: Introductionmentioning

confidence: 99%

New kinetic model for the rapid step of calcium oxide carbonation by carbon dioxide

Rouchon

Favergeon

Pijolat

2013

J Therm Anal Calorim

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To cite this version:Lydie Rouchon, Loïc Favergeon, Michèle Pijolat. A new kinetic model for the rapid step of calcium oxide carbonation by carbon dioxide. Journal of Thermal Analysis and Calorimetry, Springer Verlag, 2014, 116 (3) Keywords:Carbonation, Calcium oxide, Kinetic modeling, TG AbstractCarbonation of solid calcium oxide by gaseous carbon dioxide was monitored by thermogravimetry (TG). A kinetic model of CaO carbonation is proposed in order to interpret the first rapid step of the reaction. By taking into account the existence of large induction period as well as the sigmoidal shape of the kinetic curves in this kinetic-controlled region, a surface nucleation and isotropic growth kinetic model based on a single nucleus per particle is proposed and the expressions of the fractional conversion and the reaction rate versus time are detailed. The induction period is found to have a linear variation with respect to temperature and to follow a power law with respect to CO 2 partial pressure. The areic reactivity of growth decreases with temperature increase, and increases with CO 2 partial pressure increase. A mechanism of CaCO 3 growth is proposed to account for these results and to determine a dependence of the areic reactivity of growth on the temperature and the CO 2 partial pressure.

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The decrease of carbonation efficiency of CaO along calcination–carbonation cycles: Experiments and modelling

Cited by 59 publications

References 21 publications

Enhanced CO₂ adsorption capacity and stability using CaO‐based adsorbents treated by hydration

Enhanced CO₂ adsorption capacity and stability using CaO‐based adsorbents treated by hydration

Analysis of the kinetic slowing down during carbonation of CaO by CO2

New kinetic model for the rapid step of calcium oxide carbonation by carbon dioxide

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The decrease of carbonation efficiency of CaO along calcination–carbonation cycles: Experiments and modelling

Cited by 59 publications

References 21 publications

Enhanced CO2 adsorption capacity and stability using CaO‐based adsorbents treated by hydration

Enhanced CO2 adsorption capacity and stability using CaO‐based adsorbents treated by hydration

Analysis of the kinetic slowing down during carbonation of CaO by CO2

New kinetic model for the rapid step of calcium oxide carbonation by carbon dioxide

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Product

Resources

About

Enhanced CO₂ adsorption capacity and stability using CaO‐based adsorbents treated by hydration

Enhanced CO₂ adsorption capacity and stability using CaO‐based adsorbents treated by hydration