Structural changes in coal chars after pressurized pyrolysis

Jiménez, Francisco Jiménez; Mondragón, Fanor; López, Diana

doi:10.1016/j.jaap.2012.02.003

Cited by 25 publications

(14 citation statements)

References 26 publications

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“…The quantitative analysis of catalysts is relatively easy but the direct quantification of char structural features is a challenge. Raman spectroscopy has been used as a powerful technique to obtain information about the carbon skeleton in char during the pyrolysis/gasification of low-rank coals [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] and biomass 27]. The reaction pathways between gasification in O2, CO2 and H2O are different at 800 °C [9,18,19].…”

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confidence: 99%

Changes in nascent char structure during the gasification of low-rank coals in CO2

Zhang

Kajitani

Umemoto

et al. 2015

Fuel

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confidence: 99%

Changes in nascent char structure during the gasification of low-rank coals in CO2

Zhang

Kajitani

Umemoto

et al. 2015

Fuel

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“…Information about their internal structure that is unobtainable by other methods can be obtained. [9][10][11][12][13][14][15][16][17][18] The Raman spectra of amorphous carbon appear around 1 150, 1 350, 1 500, and the 1 620 cm -1 , and are respectively referred to as D4, D1, D3, and D2. The D4 band is supposed to be attributed to an imperfect graphite lattice, polyene, and the impurity originated by oscillation symmetric with A1g.…”

Section: Samples Usedmentioning

confidence: 99%

Coking Technology Using Heavy Oil Residue and Hyper Coal

2014

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Oil sand bitumen and hypercoal are examined as a caking additives to the mixture of strongly coking coal and non-slightly coking coal. Samples were coked, then their strength, crystallinity of the carbon structure, and an anisotropic microstructure were measured. Oil sand bitumen addition enhanced strength, but 15% addition caused a strength decline because of the formation of large pores and cracks. Hypercoal addition increased strength with increased its content. Correlation was observed between increased strength and the crystallinity of a carbon structure or the anisotropic microstructure. Results suggest that mutual melting occurred between a coal blend and a caking additive. Then the caking additive took a carbon structure with high crystallinity by coking, achieved a function as a binder material that connects coal-particle interfaces, and ultimately enhanced strength.

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“…The morphology of the char samples prepared from low‐rank coal samples were analyzed by Jiménez et al . . Their results showed that differences among pyrolysis pressures, as determined by SEM microscopy, were not consistent with the specific surface areas of the samples as measured by N 2 ‐BET analysis because of secondary pyrolysis and tar readsorption.…”

Section: Introductionmentioning

confidence: 99%

“…Various nondestructive techniques such as scanning electron microscopy (SEM), laser light scattering, and Fourier transform infrared (FTIR) spectrometry can be applied to study the structural characterization. The morphology of the char samples prepared from low-rank coal samples were analyzed by Jim enez et al [9]. Their results showed that differences among pyrolysis pressures, as determined by SEM microscopy, were not consistent with the specific surface areas of the samples as measured by N 2 -BET analysis because of secondary pyrolysis and tar readsorption.…”

Section: Introductionmentioning

confidence: 99%

Comparative study on structural properties and combustion kinetics of Chinese Shenhua long flame raw coal and its pyrolytic char

Wang

Song

Zhou

et al. 2017

Env Prog and Sustain Energy

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Research on the structural and combustion properties of coal is of great importance for its conversion and applications in view of fundamental studies. In this work, we conducted the first detailed study on the structural properties and combustion kinetics of Chinese Shenhua raw coal (RC) and its pyrolytic char (PC). The combustion kinetics was simulated by using the random pore model (RPM). The results showed that RC and PC were composed of both a plant‐cell‐like structure and a discrete particulate structure. In addition, PC had a larger specific surface area, finer particles, higher aromaticity, and higher degree of aromatic ring condensation than those of RC. Combustion of PC showed higher ignition temperature, lower burnout temperature, and a higher combustion index compared to RC. A high correlation coefficient R2 (0.999) and a low average error θ (0.008) were obtained using the RPM. The combustion apparent activation energy E and the structural parameter ψ of RC were 40.30 kJ mol−1 and 0.53, respectively. For PC, the values of E and ψ were estimated to be 60.01 kJ mol−1 and 0, respectively. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 766–774, 2017

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Structural changes in coal chars after pressurized pyrolysis

Cited by 25 publications

References 26 publications

Changes in nascent char structure during the gasification of low-rank coals in CO2

Changes in nascent char structure during the gasification of low-rank coals in CO2

Coking Technology Using Heavy Oil Residue and Hyper Coal

Comparative study on structural properties and combustion kinetics of Chinese Shenhua long flame raw coal and its pyrolytic char

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