Reaction mechanism of carbon gasification in CO2 under non-isothermal conditions

Liu, Zhongsuo; Wang, Qi; Zong-shu, Zou; Tan, Guang-Lei

doi:10.1007/s10973-010-1238-2

Cited by 12 publications

(4 citation statements)

References 13 publications

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“…The lowestEb for the chemisorption of CO2 gas molecule at Czi active site is indicative of a nearly barrierless reaction and shows a good correlation with the highest f + (r) value reported in Table 4. The values are for the particular molecular model containing all of the active sites stipulated but are consistent with reports of chemisorption of CO2 on various carbonaceous models as an exothermic process associated with low adsorption energies [28,43,[121][122][123]. Table 5.…”

Section: Co2 Chemisorption On Reactive Edgesupporting

confidence: 86%

Density functional theory molecular modelling and experimental particle kinetics for CO2–char gasification

Roberts

Everson

Domazetis

et al. 2015

Carbon

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Experimental measurements and DFT atomistic modelling were conducted to elucidate the mechanisms for gasification chemistry of char with CO2 gas. The molecular models used were based on experimental representations of coal chars derived from the vitrinite-and inertinite-rich South African coals at 1000 . The HRTEM and XRD techniques were used to construct parallelogram-shaped PAH stacks of highest frequency in the vitrinite-rich (7x7) and intertinite-rich (11x11) char structures. Computations were executed to get the nucleophillic Fukui functions, at DFT-DNP level, to elucidate the nature and proportions of carbon active sites and quantify their reactivity. The DFT-DNP-computed reaction pathways and transition states, to obtain the energy of reaction and activation energies for the gasification reactions of CO2 with active carbon sites were examined. These results were compared with TGA experimental results at 900-980 . The mean nucleophillic Fukui function of the H-terminated char models and active sites located at similar edge positions

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Section: Co2 Chemisorption On Reactive Edgesupporting

confidence: 86%

Density functional theory molecular modelling and experimental particle kinetics for CO2–char gasification

Roberts

Everson

Domazetis

et al. 2015

Carbon

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“…33,34 And then the fast gasification stage began, while the chemisorption step stopped. 33 Although many mechanisms have been put forward to interpret carbon gasification process, 13,35,36 none have been accepted widely due to the difficulty of in situ observation of the evolution of molecules in the whole reaction process. However, the entire carbon gasification process can be monitored using thermogravimetry, which has been widely applied to study the kinetics of carbon gasification.…”

Section: Resultsmentioning

confidence: 99%

“…A process of weight gain was observed before the weight loss in both graphite and coke gasification. Two stages were proposed to explain this reaction process in a recent study . The initial stage was an exothermic slow gasification stage caused by the combined effect of the exothermic chemisorption and the endothermic chemical reaction. , And then the fast gasification stage began, while the chemisorption step stopped .…”

Section: Resultsmentioning

confidence: 99%

“…Two stages were proposed to explain this reaction process in a recent study . The initial stage was an exothermic slow gasification stage caused by the combined effect of the exothermic chemisorption and the endothermic chemical reaction. , And then the fast gasification stage began, while the chemisorption step stopped . Although many mechanisms have been put forward to interpret carbon gasification process, ,, none have been accepted widely due to the difficulty of in situ observation of the evolution of molecules in the whole reaction process.…”

Section: Resultsmentioning

confidence: 99%

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Gasification of Graphite and Coke in Carbon–Carbon Dioxide–Sodium or Potassium Carbonate Systems

Li¹,

Zhang²,

Liu³

et al. 2014

Ind. Eng. Chem. Res.

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The thermodynamics of possible reactions, including gasification and reduction reactions, in carbon–carbon dioxide–sodium or potassium carbonate systems was analyzed first. And then, the gasification reactions of graphite and coke with CO2 in this system were studied kinetically by temperature programmed thermogravimetry. The results showed that the carbon conversion curve shifted to a lower temperature zone after Na2CO3 or K2CO3 was added, and graphite was more susceptible than coke to be catalyzed by Na2CO3 or K2CO3. Ten kinetic equations were adopted to simulate the reaction process using the method of Coats–Redfern. The Avrami–Erofeev equation was found to be the most probable kinetic equation, with which the values of activation energy and frequency factor were calculated. The kinetic simulation indicated that the activation energy of coke carbon had been activated to the lowest level by its inner factors, thus it was difficult to be reduced by adding Na2CO3 or K2CO3. The kinetic compensation effect was confirmed to exist in both graphite gasification and coke gasification. X-ray diffraction and Raman spectra were used to characterize the inner difference between graphite and coke, which showed that coke carbon structure was greatly different from graphite structure because of its highly disordered and heterogeneous carbon structure.

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Experimental study on cogasification mechanisms of straw and kitchen waste in the fixed‐bed gasifier

Shan

Wang

et al. 2020

Int J Energy Res

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Reaction mechanism of carbon gasification in CO2 under non-isothermal conditions

Cited by 12 publications

References 13 publications

Density functional theory molecular modelling and experimental particle kinetics for CO2–char gasification

Density functional theory molecular modelling and experimental particle kinetics for CO2–char gasification

Gasification of Graphite and Coke in Carbon–Carbon Dioxide–Sodium or Potassium Carbonate Systems

Experimental study on cogasification mechanisms of straw and kitchen waste in the fixed‐bed gasifier

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