Evolution of surface functional groups of coal char during coal combustion under <scp>O<sub>2</sub>/CO<sub>2</sub></scp> atmospheres

Yan, Dawei; Gu, Mingyan; Lin, Yu-Yu; Chen, Ping; He, Xin

doi:10.1002/apj.2170

Cited by 6 publications

(3 citation statements)

References 26 publications

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“…The sensitivities of different reactive functional groups to oxygen concentration were analysed (Zhao et al 2022). Zhao et al (2019a) and Mustafa Baysal et al (2016) studied the microscopic characteristics of coal under different conditions (high-temperature oxidation, varying temperatures, oxygen contents, chemical composition, and degree of ordered structure); by using the FTIR approach, the relationships among free radicals, apparent activation energy, and the characteristics of surface functional groups were examined in low-temperature oxidations and in O 2 or CO 2 atmospheres (Zhang et al 2019;Xu et al 2018;Yan et al 2018;Wang et al 2018a, b).…”

Section: Introductionmentioning

confidence: 99%

Experimental study on the oxidation kinetics of coal in typical coal mining areas of the Southern Junggar coalfield, Xinjiang, China

Zeng

2022

Int J Coal Sci Technol

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Coal spontaneous combustion (CSC) is a disaster associated with coal mining that leads to loss of coal resources and environmental and human health issues. To investigate kinetic characteristics for oxidation of coal, three coal samples were collected from different coal mining areas in the Southern Junggar coalfield. Subsequently, the collected coal samples were ground into different particle sizes and tested using microscopic and macroscopic methods, including thermal gravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, and temperature-programmed oxidation. The results obtained are as follows: the sharpest absorption peak (002) indicates that graphitization is high. Furthermore, the results show that the SKS coal sample is prone to spontaneous combustion; the greater the aromatic hydrocarbon content is, the more difficult it is for CSC to occur, while the opposite is true for oxygen-containing functional groups. The SKS data confirmed this conclusion; the rate for generation of CO and CO2 controlled the possibility of SKS oxidation at 110 °C and provided an indication of the temperature. During the dehydration stage, the WD sample had the lowest activation energy, indicating that it was most susceptible to spontaneous combustion. During the combustion stage, the lowest activation energy was found for the SKS sample with particle sizes < 0.075 mm, indicating that particle size was one of the factors affecting spontaneous combustion. The activation energy for dehydration was significantly lower than that for combustion, which showed that the coal oxygen reaction was more likely to occur in the dehydration stage. Based on DSC curves, the SKS sample had the largest exothermicity, indicating that it would ignite more readily.

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Section: Introductionmentioning

confidence: 99%

Experimental study on the oxidation kinetics of coal in typical coal mining areas of the Southern Junggar coalfield, Xinjiang, China

Zeng

2022

Int J Coal Sci Technol

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“…Its nano composites have become one of the hot spots of scholars from various countries. [28][29][30][31] Some scholars studied the composite material formed by GO and silk fibroin and used silk fibroin and GO hydrogel to prepare a composite membrane material with a layered structure and excellent mechanical properties. 32 Most of these methods have the disadvantages of complex process, harsh conditions and easy to produce pollution.…”

Section: Introductionmentioning

confidence: 99%

Natural flat cocoon materials constructed by eri silkworm with high strength and excellent anti-ultraviolet performance

Zhou

Wang

Zhou³

et al. 2020

Journal of Engineered Fibers and Fabrics

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Eri silkworm is easy to be raised and has high cocoon yield, the cocoon fails to be continuously reeled due to a loose structure, a large part of cocoon coat and an eclosion hole. In this work, a fifth instar larvae of eri silkworm was provided with only a flat cocooning place to spin to produce a flat cocoon, it was fed with the castor leaves sprayed with nano-TiO2 and graphene oxide (GO), Compared with the flat cocoon obtained without nanomaterials, the silk was not found to change in morphology and structure significantly. Nanomaterials promoted the transformation of the random coil/α-helix conformation of the silk to the β-sheet conformation to a certain extent, which formed a stable crystallization. Thus its strength value could increase by 15%–17%, the ultraviolet protection factor ( UPF) value of the flat cocoon with nanomaterials increased significantly, and the silk obtained made up for the lack of the strength in natural eri silkworm silk and poor resistance to sunlight. The flat cocoon features a stable structure, good formation, uniform thickness, and manual control. It can be directly used as raw material for processing flat textile products, which provides a feasible idea for the high-value utilization of the eri silkworm cocoon.

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“…examined the relationship between free radicals, apparent activation energy, and functional groups in the low-temperature oxidation process of Jurassic coal in northern Shaanxi. Using the FTIR approach, (Yan et al, 2018) quantitatively analysed the characteristics of surface functional groups of coal coke in an O 2 or CO 2 atmosphere. (Pan et al, 2020) used XRD and FTIR to comparatively analyse the rate of change in the coal oxidation microstructures under varying temperatures and oxygen conditions.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of the major coal seam in typical coal mining areas of Southern Junggar coalfield, Xinjiang, China

Shen

Zeng

2020

Preprint

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In the present study, the authors collected coal samples from the Wudong (WD), Dahuangshan (DHS), and Sikeshu (SKS) coal mines in the Southern Junggar coalfield. The collected coal was ground into particle sizes of 0.25–0.38 mm, 0.15–0.18 mm, 0.109–0.12 mm, 0.08–0.096 mm, and <0.075 mm. The experimental data was acquired using diverse methods, such as in situ infrared spectroscopic analysis, temperature-programmed oxidation, and thermogravimetric analysis. The results show that the number of oxygen-containing functional groups increased with the decline in particle size, indicating that a smaller particle size may facilitate oxidation reactions and spontaneous coal combustion. On the basis of the analysis of the elements of coal samples, it can be concluded that the proportion of oxygen elements of coal samples in three mining areas is: WD＞SKS＞SHS. The oxygen consumption rate of the DHS and WD coal samples increased exponentially when the temperature increased; the rate of SKS coal samples initially rose significantly and then decreased. The gas generation rates for the different gases indicated that temperatures of 90 ℃ or 130 ℃ could accelerate the oxidation reaction. The pollutants produced by the oxidation of the SKS coal samples were higher than those by DHS and WD. For all particle diameters, the T3 for the SKS samples is smaller than that for WD and DHS, indicating that the SKS coal sample will combust more readily. With the decrease in particle size, the activation energy showed an increase in low-temperature oxidation stage. While the activation energy of the WD and SKS samples decreased in high temperature stage, that of the DHS increased before decreasing. A lower of activation energy means that the coal will have a higher risk of spontaneous combustion. Based on the differential scanning calorimetry (DSC) curve, SKS coal sample has the highest exothermic heat, the DHS has the second, and WD has the least. With a higher exothermic heat, the coal sample will more readily ignite.

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Evolution of surface functional groups of coal char during coal combustion under O₂/CO₂ atmospheres

Cited by 6 publications

References 26 publications

Experimental study on the oxidation kinetics of coal in typical coal mining areas of the Southern Junggar coalfield, Xinjiang, China

Experimental study on the oxidation kinetics of coal in typical coal mining areas of the Southern Junggar coalfield, Xinjiang, China

Natural flat cocoon materials constructed by eri silkworm with high strength and excellent anti-ultraviolet performance

Kinetics of the major coal seam in typical coal mining areas of Southern Junggar coalfield, Xinjiang, China

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Evolution of surface functional groups of coal char during coal combustion under O2/CO2 atmospheres

Cited by 6 publications

References 26 publications

Experimental study on the oxidation kinetics of coal in typical coal mining areas of the Southern Junggar coalfield, Xinjiang, China

Experimental study on the oxidation kinetics of coal in typical coal mining areas of the Southern Junggar coalfield, Xinjiang, China

Natural flat cocoon materials constructed by eri silkworm with high strength and excellent anti-ultraviolet performance

Kinetics of the major coal seam in typical coal mining areas of Southern Junggar coalfield, Xinjiang, China

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Evolution of surface functional groups of coal char during coal combustion under O₂/CO₂ atmospheres