Structural characterization of coking component of an Indian coking coal

Mohanty, Ashok; Chakladar, Saswati; Mallick, Subhajit; Chakravarty, Sanchita

doi:10.1016/j.fuel.2019.03.108

Cited by 50 publications

(8 citation statements)

References 31 publications

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“…The (100) peak represents the size of an aromatic carbon sheet. A higher peak corresponds to a higher condensation degree of aromatic nuclei [ 29 , 30 ].…”

Section: Resultsmentioning

confidence: 99%

A comprehensive investigation of the reaction behaviorial features of coke with different CRIs in the simulated cohesive zone of a blast furnace

Tian

Zhou

et al. 2021

PLoS ONE

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The reaction characteristics and mechanism of coke with different coke reactivity indices (CRIs) in the high-temperature zone of a blast furnace should be fully understood to correctly evaluate the coke quality and optimize ironmaking. In this work, low-CRI coke (coke A) and high-CRI coke (coke B) were charged into a thermogravimetric analyzer to separately study their microstructural changes, gasification characteristics, and reaction mechanism under simulated cohesive zone conditions in a blast furnace. The results show that both coke A and coke B underwent pyrolysis, polycondensation, and graphitization during the heat treatment. The pyrolysis, polycondensation, gasification speed, and dissolution speed rates of coke B were higher than those of coke A. Direct and indirect reduction between sinter and coke occurred in the cohesive zone and had different stages. The consumption rate of coke B was faster than that of coke A during the coke–sinter reduction. The carbon molecules of coke A must absorb more energy to break away from the skeleton than those of coke B.

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“…The (100) peak represents the size of an aromatic carbon sheet. A higher peak corresponds to a higher condensation degree of aromatic nuclei [ 29 , 30 ].…”

Section: Resultsmentioning

confidence: 99%

A comprehensive investigation of the reaction behaviorial features of coke with different CRIs in the simulated cohesive zone of a blast furnace

Tian

Zhou

et al. 2021

PLoS ONE

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“…The diffraction phase corresponding to the diffraction peak at other positions is kaolinite with little change; it has no effect on the adsorption performance of the coking coal. 25…”

Section: Resultsmentioning

confidence: 99%

“…New pores are created during the dissolution process; this is the reason why specific surface area increased. The diffraction phase corresponding to the diffraction peak at other positions is kaolinite with little change; it has no effect on the adsorption performance of the coking coal …”

Section: Resultsmentioning

confidence: 99%

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Effect of Different Acid-Modified Coking Coals on Quinoline Adsorption

Wang

Ning

et al. 2019

ACS Omega

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The adsorption of quinoline from wastewater by coking coal (AC-1), HCl-modified coking coal (AC-2), HNO3-modified coking coal (AC-3), HF-modified coking coal (AC-4), and H2SO4-modified coking coals (AC-5) was investigated in this paper. The effects of acid-modified concentration, modification time, and adsorption time versus quinoline removal rate were studied by batch experiments. The quinoline concentration was measured by UV spectrophotometry, the average pore size and specific surface area of coking coal before and after modification were characterized through static nitrogen adsorption, the mineral composition of coking coal was tested by X-ray diffraction, the surface functional groups were tested by Fourier transform infrared spectroscopy, and the surface topography was tested using a scanning electron microscope. The experimental results showed that the adsorption capacity of coking coals was the best when both the modification time was 120 min and the acid-modified concentration was 0.1 mol·L–1 and the quinoline removal rate reaches the highest when the adsorption time was 120 min. The specific surface area of AC-2 increased from 2.898 to 3.637 m2·g–1, and the removal rate of quinoline increased from 77.64 to 90.61%. Acids reacted with inorganic mineral impurities within coking coal such as hydrogen vanadium phosphate hydrate, which caused an increase in the specific surface area. A new peak appeared in the Fourier transform infrared spectroscopy pattern at the wavenumber 2300 cm–1. The surface of coking coal modified by acids was rougher than that of AC-1. The adsorption capacity of coking coal was improved after modification, and modified coking coals have the highest potential as low-cost adsorbents for quinoline removal.

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“…The heterogeneity of the coal microstructure makes it difficult to characterize the chemical structure by a single technique, and thus more extensive techniques are required to provide an in-depth knowledge of coal properties. With the high-tech software progress and technological development prompting the emergence of modern analytical methods, extensive efforts have been made by many researchers, including Fourier transform infrared (FTIR), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectrometer (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM), etc. − Among them, compared with other instrumental techniques for probing the internal microstructure of carbon-containing materials, Raman spectroscopy and XRD exhibit significant advantages of not only being able to detect the mineral composition and carbon skeleton in coal but also being able to provide a higher resolution of coal macromolecular structures and being more sensitive to microstructural changes than other analytical techniques. , The application of Raman spectroscopy and XRD in the characterization of coal structures has been extensively investigated in previous studies. ,, In addition, for the microporous structure of coal, the physisorption method (CO 2 as the probe molecule) is generally adopted to carry out morphological analysis . Although CO 2 (273 K) could effectively analyze the micropores of 0.35–1.5 nm with a small molecular dynamics diameter and short adsorption time, the characterization of ultra-micropores is still insufficient.…”

Section: Introductionmentioning

confidence: 99%

Morphological Characterization of the Microcrystalline Structure of Tectonic Coal and Its Intrinsic Connection with Ultra-micropore Evolution

et al. 2022

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A systematic knowledge of the physical and chemical microstructure of coal is indispensable for better understanding gas storage and migration, and the variations of coal microcrystalline morphological structures have significant impacts on the ultra-micropore development at the molecular scale. However, the response mechanism of metamorphism and tectonism on ultra-microporous evolution in the macromolecular structure still needs further study. In this work, the microcrystalline morphological structure of original and tectonic coals and its essential relation with ultra-micropore evolution were investigated via XRD, Raman spectroscopy, and CO2 (273 K) adsorption. The results demonstrate that the XRD patterns of high-rank tectonic coals have sharper and right-shifted 002 bands compared to those of lower-rank original coals, and tectonic deformation factors may affect the development characteristics of coal microcrystalline structures. The relative content of kaolinite in high-rank tectonic coals increases, whereas that of quartz decreases; tectonism has a great influence on the composition of silicate minerals. With the enhancement of metamorphism and tectonism, the aromatic interlayer spacing d 002 decreases from 0.3651 to 0.3482 nm, while the stacking height Lc and the aromatic slices Nave increase by 60.7 and 68.6%, respectively, promoting the degree of aromatization fa and degree of graphitization g. Tectonism further advances the evolution of the above structural parameters. In addition, the peak position difference G – D 1 of Raman spectrum has a sensitive response to metamorphism and tectonism. The peak intensity ratio I D1/IG is directly negatively correlated with metamorphism, and tectonism brings about a further decrease. In this case, the degree of crystallinity in the basic structural units increases, and the degree of large-scale defects in the crystal decreases, contributing to the well-developed microporous structure of original and tectonic coals with different ranks. Metamorphism facilitates the ordered macromolecular structural evolution on aromatization and condensation, and subsequently, tectonism results in the intensive recombination, stacking, condensation, and aromatization of microcrystalline structures in advance. Thus, this combination may lead to the macromolecular structure evolution from disordering to ordering and then essentially alter the chemical structure of tectonic coal. The aforementioned results have guiding significance for revealing the gas sorption and diffusion behaviors as well as the mechanism of coalbed methane generation, storage, and migration.

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Structural characterization of coking component of an Indian coking coal

Cited by 50 publications

References 31 publications

A comprehensive investigation of the reaction behaviorial features of coke with different CRIs in the simulated cohesive zone of a blast furnace

A comprehensive investigation of the reaction behaviorial features of coke with different CRIs in the simulated cohesive zone of a blast furnace

Effect of Different Acid-Modified Coking Coals on Quinoline Adsorption

Morphological Characterization of the Microcrystalline Structure of Tectonic Coal and Its Intrinsic Connection with Ultra-micropore Evolution

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