A study of the relationships between coal structures and combustion characteristics: The insights from micro-Raman spectroscopy based on 32 kinds of Chinese coals

Xu, Jun; Tang, Hao; Su, Sheng; Liu, Jiawei; Xu, Kai; Qian, Kun; Wang, Lele; Zhou, Yongqiang; Zhang, Anchao

doi:10.1016/j.apenergy.2017.11.094

Cited by 110 publications

(75 citation statements)

References 58 publications

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“…Variations of the carbon structure of biomass char during steam gasification by FT-Raman spectroscopy has been reported [20]. A good dependence of combustion reactivity on the Raman band area ratios has been revealed in reference [17] and the correlation between ignition temperature of coals and Raman spectral parameters has been further demonstrated [21].…”

Section: Introductionmentioning

confidence: 95%

“…Moreover, the Raman spectroscopic studies were shown to be complementary to FTIR spectroscopic analyses. Although a number of studies [21,[23][24][25] have been conducted on the Raman spectra of coals or coal ashes separately, very little research has been carried out on the Raman spectra of raw coals and resulting coal ashes. Furthermore, Raman spectral changes from raw coals to resulting coal ashes have not yet been reported.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Coals and Coal Ashes with High Si Content Using Combined Second-Derivative Infrared Spectroscopy and Raman Spectroscopy

Yin

et al. 2019

Crystals

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The organic and mineral components in two coals and resulting high-temperature ashes with high silicon content were characterized by second-derivative infrared spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD). The infrared spectra of raw coals show weak organic functional groups bands but strong kaolinite bands because of the relatively high silicates content. In contrast, the Raman spectra of raw coals show strong disordered carbon bands but no mineral bands since Raman spectroscopy is highly sensitive to carbonaceous phases. The overlapping bands of mineral components (e.g., calcite, feldspar, and muscovite) were successfully resolved by the method of second-derivative infrared spectroscopy. The results of infrared spectra indicate the presence of metakaolinite in coal ashes, suggesting the thermal transformation of kaolinite during ashing. Intense quartz bands were shown in both infrared and Raman spectra of coal ashes. In addition, Raman spectra of coal ashes show a very strong characteristic band of anatase (149 cm–1), although the titanium oxides content is very low. Combined use of second-derivative infrared spectroscopy and Raman spectroscopy provides valuable insight into the analyses of mineralogical composition. The XRD results generally agree with those of FTIR and Raman spectroscopic analyses.

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Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Characterization of Coals and Coal Ashes with High Si Content Using Combined Second-Derivative Infrared Spectroscopy and Raman Spectroscopy

Yin

et al. 2019

Crystals

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“…A D3 /A (G + D2 + D3) was found to have fairly good linear correlations with the T 20% of the lignite chars generated from 500 C to 1400 C. Morga et al [149] studied the structure of 18 kinds of coal char and found that the reactivity index of coal char was related to the FWHM of the D 2 , G, and D 4 bands. Xu et al [150] reported A D /A all can act as a useful indicator for coal combustion characteristics. Nevertheless, these studies are still limited, creating a lack of fully resolved conclusions based on the empirical evidence.…”

Section: Study Of Reactivity Of Charmentioning

confidence: 99%

Progress of Raman spectroscopic investigations on the structure and properties of coal

Xia

Wang

et al. 2020

J Raman Spectroscopy

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Raman spectroscopy is a nondestructive and in situ analytical technique that could provide information on the chemical structure and structural ordering of carbonaceous materials. Based on the E2g symmetric stretching vibration mode in the aromatic layers (G band, ~1,580 cm−1) and the defect structure in graphite (D band, ~1,350 cm−1), Raman spectroscopy has been used extensively to characterize the structural features of carbonaceous matters since 1970. Coal is a complex organic compound made up mainly by carbon showing characteristic Raman bands. This article reviews the application of Raman spectroscopy for coal structure characterization under room temperature, to determine its chemical structure, crystallite size, coal rank, and combustion reactivity. Future research for collecting Raman spectra during coal pyrolysis at high temperatures is also discussed. The combination of high‐temperature hot stage with Raman spectroscopy technology allows direct collection of Raman spectra at high temperature.

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“…Li et al (2019b) studied the transformation of kinetic mode and the kinetic compensation effect during coal spontaneous combustion. Moreover, researchers also explored the evolution of coal structures to reveal the essential causes of coal spontaneous combustion (Wang et al 2020a(Wang et al , 2020cXu 2017;Xu et al 2018;Zhou et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Thermokinetic Characteristics of Coal Combustion under High Temperatures and Oxygen–Limited Atmospheres

Wang

Duan

Xiao

et al. 2020

Combustion Science and Technology

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Coal fires are widespread in the coal-major producing countries, which causes serious environmental issues due to the high temperature and hazardous gases during coal combustion. Under oxygen-depleted atmospheres, the thermal behaviors and kinetic characteristics during coal combustion at high temperatures were paid more attention by the method of TG-DSC synchronous thermal analysis. The results indicate that the focused weightlessness and heat release processes became scattered under oxygen-depleted atmospheres, and the influence of oxygen concentration obviously increased when it was below 13 vol.%. The mass presented a linear correlation to the quantity of heat release, and the relationship between the mass and quantity of heat release showed stage characteristics with oxygen concentration. Moreover, the kinetic modes transformed from random nucleation and subsequent growth to contractive sphere, and the critical oxygen concentrations are consistent to these of thermal behaviors. These findings are significant for better understanding the characteristics of coal spontaneous combustion at high-temperature and under low-oxygen concentrations.

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A study of the relationships between coal structures and combustion characteristics: The insights from micro-Raman spectroscopy based on 32 kinds of Chinese coals

Cited by 110 publications

References 58 publications

Characterization of Coals and Coal Ashes with High Si Content Using Combined Second-Derivative Infrared Spectroscopy and Raman Spectroscopy

Characterization of Coals and Coal Ashes with High Si Content Using Combined Second-Derivative Infrared Spectroscopy and Raman Spectroscopy

Progress of Raman spectroscopic investigations on the structure and properties of coal

Thermokinetic Characteristics of Coal Combustion under High Temperatures and Oxygen–Limited Atmospheres

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