A thermal behavior study of Chinese coals with high hydrogen content

Wang, Shaoqing; Tang, Yuegang; Schobert, Harold H.; Mitchell, Gareth D.; Liao, Fengrong; Zeng-zhi, Liu

doi:10.1016/j.coal.2009.10.012

Cited by 39 publications

(38 citation statements)

References 29 publications

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“…Mae et al [10] reported the relationship of the yield of pyrolysis products with coal structure. Wang et al [11] studied the structure and pyrolysis characteristics of Chinese western coals, demonstrating the relationship between evolution of coal composition and its physicochemical structure. On the basis of X-ray, studies of coal reported by many researchers [12][13][14] show that the X-ray diffraction pattern of coal resembles a very blurred graphite pattern similar to that obtained with activated carbons and carbon black.…”

Section: Introductionmentioning

confidence: 99%

Evolution Mechanism of Macromolecular Structure in Coal during Heat Treatment: Based on FTIR and XRD In Situ Analysis Techniques

Zhang

2019

Journal of Spectroscopy

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Owing to the complexity and heterogeneity of coal during pyrolysis, the ex situ analytical techniques cannot accurately reflect the real coal pyrolysis process. In this study, according to the joint investigation of Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), the structural evolution characteristics of lignite-subbituminous coal-bituminous coal-anthracite series under heat treatment were discussed in depth. e results of the infrared spectrum of coal show that the different functional groups of coal show different changes with the increase of coal rank before pyrolysis experiment. Based on in situ infrared spectroscopy experiments, it was found that the infrared spectrum curves of the same coal sample have obvious changes at different pyrolysis temperatures. As a whole, when the pyrolysis temperature is between 400 and 500°C, the coal structure can be greatly changed. By fitting the infrared spectrum curve, the infrared spectrum parameters of coal were obtained. With the change of temperature, these parameters show regular changes in coal with different ranks. In the XRD study of coal, the absorption intensity of the diffraction peak (002) of coal increases with increasing coal rank. e XRD patterns of coal have different characteristics at different pyrolysis temperatures. Overall, the area of (002) diffraction peak of the same coal sample increases obviously with the increase of temperature. e XRD structural parameter of coal was obtained by using the curve fitting method. e changing process of two parameters (interlayer spacing (d 002 ) and stacking height (L c )) can be divided into two main stages, but the average lateral size (L a ) does not change significantly and remains at the 2.98 ± 0.09 nm. In summary, the above two technologies complement each other in the study of coal structure. e temperature range of both experiments is different, but the XRD parameters of coal with different ranks are reduced within the temperature range of less than 500°C, which reflects that the size of coal-heated aromatic ring lamellae is reduced and the distance between lamellae is also reduced, indicating that the degree of condensation of coal aromatic nuclei may be increased. Correspondingly, the FTIR parameters of coal also reflect that, with increasing temperature, the side chains of coal are constantly cracked, the oxygen-containing functional groups are reduced, and the degree of aromatization of coal may be increased.

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Section: Introductionmentioning

confidence: 99%

Evolution Mechanism of Macromolecular Structure in Coal during Heat Treatment: Based on FTIR and XRD In Situ Analysis Techniques

Zhang

2019

Journal of Spectroscopy

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“…Fig 1 shows that the loss of heat to the environment after the combustion of the coal was both small and very slow and therefore the corresponding error is negligible. o C, there is a broad upwards peak between them showing that the decomposition is exothermic [8,9]. …”

Section: Heats Of Combustionmentioning

confidence: 99%

“…The further decrease in % weight corresponding to the second peak is believed to be due to the primary exothermic devolatilisation process in which compounds containing carbon, hydrogen and oxygen are released. Peak three indicates the secondary endothermic degasification process in which methane and hydrogen are released [8].…”

Section: Differential Thermal Analysismentioning

confidence: 99%

Thermal-Gravimetric, Calorimetric and Chemical Analytical Characterisation of Coal

Nadiye-Tabbiruka

Ddamba²,

Tsheko³

et al. 2014

IJMSA

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Abstract:Coal samples from Morupule colliery in Botswana were characterized by bomb calorimetry, thermal-gravimetric analysis, atomic absorption spectrometry and flame photometry. The average heat of combustion of the coal was found to be 27.3 kJ g -1 ; with a substantial amount of ashes left behind. Thermo-gravimetric analysis showed peaks at 59.40 o C corresponding to loss of surface water, an exothermic peak at 448.54 0 C associated with primary devolatilization in which compounds containing carbon, hydrogen and oxygen are released and finally a second exothermic peak at 682.58 0 C associated with the secondary degasification in which methane and hydrogen are released. 70.4% of the coal was left after heating to 1000 0 C indicating that in its present form, Morupule coal is of low quality but releases plenty of heat on combustion. The determination of the percentage weights of Calcium, Chromium, Copper, Lead, Iron using Atomic Absorption Spectrometry (AAS) and that of Potassium and Sodium using flame photometry showed that Iron (21.0956%) is the dominant inorganic element. The percentage weights of the other elements varied between zero and 7.4301%.

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“…Hydrogen-rich coal refers to coal for which the hydrogen content is not less than 5.0%. This special type of coal is characterized not only by a high hydrogen content but also by high H/C atomic ratios (Chen et al, 1991;Wang et al, 2010Wang et al, , 2017Takahashi et al, 2014). For maceral components, the typical features of hydrogenrich coal are that they have higher levels of liptinite, such as barkinite, alginate and resinite.…”

Section: Introductionmentioning

confidence: 99%

“…For maceral components, the typical features of hydrogenrich coal are that they have higher levels of liptinite, such as barkinite, alginate and resinite. There are some special thermal properties of hydrogen-rich coal, such as a high pyrolysis rate, good hydrocarbon-generation and good liquefaction performance, which are caused by the important influence of the element hydrogen (Wang et al, 2010;. However, to our knowledge, little research has been undertaken on the organic geochemical characteristics of hydrogen-rich coal (H > 5.0%), especially the relationship between hydrogen content, source materials and depositional environment during coal formation.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Hydrogen‐rich Coals in Southern China: Implications from Organic Geochemistry and Carbon Isotopic Compositions

Lin

Wang

Yang³

et al. 2022

Acta Geologica Sinica (Eng)

Self Cite

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The organic geochemical characteristics of hydrogen‐rich coal in southern China were investigated synthetically through organic geochemistry and carbon isotope analyses. The results showed that the hydrogen contents of the test samples were more than 5.0% and the H/C atomic ratios were between 0.76–1.06. Samples were found to be composed mostly of Type II‐III kerogen, consistent with good hydrocarbon‐generation potential. The Ro (0.54–1.10%) and Tmax (430–453°C) values imply that the hydrogen‐rich coals were in low maturity to mature stages. Stable carbon isotopic ratios (δ13Corg) of the samples used varied from –24.5‰ to –23.4‰, the barkinite content ranging from 13.9% to 83.3%, indicating a predominantly terrestrial origin with marine influence during coal formation. Some organic geochemical parameters showed corresponding changes as the hydrogen content increased from 5.0% to 7.0%, however, the source inputs changed significantly when hydrogen content was greater than 6.0%. Terrestrial higher plants gradually become predominant within the coal‐forming materials, whereas this dominant position is not apparent at lower hydrogen contents, which is attributable to the strong seawater effect during the hydrogen‐rich coal formation process.

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A thermal behavior study of Chinese coals with high hydrogen content

Cited by 39 publications

References 29 publications

Evolution Mechanism of Macromolecular Structure in Coal during Heat Treatment: Based on FTIR and XRD In Situ Analysis Techniques

Evolution Mechanism of Macromolecular Structure in Coal during Heat Treatment: Based on FTIR and XRD In Situ Analysis Techniques

Thermal-Gravimetric, Calorimetric and Chemical Analytical Characterisation of Coal

Characteristics of Hydrogen‐rich Coals in Southern China: Implications from Organic Geochemistry and Carbon Isotopic Compositions

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