Effect of inorganic acid elution on microcrystalline structure and spontaneous combustion tendency of Shengli lignite

Ban, Yanpeng; Tang, Yanhua; Wang, Jie; Han, Mengxin; Te, Gusi; WANG-Yan,; He, Rong; Zhi, Keduan; Liu, Quansheng

doi:10.1016/s1872-5813(16)30047-0

Cited by 20 publications

(8 citation statements)

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“…At a normal temperature, the interactions between coal and oxygen in air produces a small amount of heat through physical adsorption, chemical adsorption, and oxidation. In addition, under certain conditions, the rate of heat production through oxidation is larger than the rate of heat dissipation to the surroundings. − Therefore, accumulation of generated heat causes a slow and steady rise in the temperature of coal, and then, the oxidation and temperature rise rates increase when the temperature reaches the critical self-heating value of coal. Finally, coal is burned after it reaches its ignition temperature.…”

Section: Experimental Results and Analysismentioning

confidence: 99%

Occurrence Mechanism and Risk Assessment of Dynamic of Coal and Rock Disasters in the Low-Temperature Oxidation Process of a Coal-Bed Methane Reservoir

Tang

Yang

2017

Energy Fuels

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The aim of this research is to explore the occurrence mechanism of dynamic disasters of coal and rocks in low-temperature oxidation of coal-bed methane (CBM) reservoirs. For this purpose, the occurrence probability of dynamic disasters at different oxidizing temperatures was assessed by using the comprehensive predictive index K for dynamic disasters involving coal and rocks. By employing nuclear magnetic resonance (NMR) technology, the evolution law of diameter and quantity of pores inside coal was detected during low-temperature oxidation of coal masses. In addition, fracture development of coal masses was monitored and analyzed by applying various instruments, including an instrument for measuring ΔP, hardness tester, gas chromatograph, and measuring system for rocks using the P-wave. The results showed that both the diameter and quantity of pores inside coal increased with the rise of the oxidizing temperature of the coal masses: the porosity increased by 72.2% as the temperature rose by 200 °C. The gas chromatograph and industrial analytical experiment proved that the whole fracture development process of coal masses was divided into two stages during low-temperature oxidation. In the initial stage of low-temperature oxidation (30–130 °C), water inside coal masses was lost and evaporated, resulting in the expansion and connection of micropores to mesopores. In the later period of low-temperature oxidation (130–230 °C), mesopores expanded and connected to macropores and microfractures because of oxygenolysis of the macromolecules and volatiles in coal. On the basis of the comprehensive predictive index K for dynamic coal disasters, the occurrence probability of dynamic disasters in low-temperature oxidation of CBM reservoirs was verified to increase with the increasing oxidizing temperature according to the measured data. In addition, the maximum allowable oxidizing temperature of the CBM reservoir where the specimen was collected was 130 °C.

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Section: Experimental Results and Analysismentioning

confidence: 99%

Occurrence Mechanism and Risk Assessment of Dynamic of Coal and Rock Disasters in the Low-Temperature Oxidation Process of a Coal-Bed Methane Reservoir

Tang

Yang

2017

Energy Fuels

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“…The filter cake from filtration was then dried under conditions same as that of SL and the dried powder was designated as SL + . The proximate and ultimate analyses of SL and SL + have been described elsewhere . The results are shown in Table .…”

Section: Methodsmentioning

confidence: 99%

“…The proximate and ultimate analyses of SL and SL + have been described elsewhere. 31 The results are shown in Table 1.…”

Section: Methodsmentioning

confidence: 99%

Graphite and Graphite Oxide: New Models to Analyze the Calcium Catalytic Effect on Steam Gasification of Lignite and Char

Ban

Liu

et al. 2019

Energy Fuels

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Graphite oxide (GO) and graphite (G) were used as Shengli lignite (SL) and char (SL+-T) models to study gasification reactivity for the first time. The steam gasification performance of SL+, SL+-T, G, GO and the corresponding Ca-added samples was evaluated in a fixed bed reactor equipped and linked with a downstream GC system. The samples were comprehensively characterized by Fourier transform infrared, XRD, Raman, X-ray photoelectron spectroscopy, and 13C NMR. Results show that calcium exerted a significant catalytic effect on the steam gasification of SL+ and GO but had a limited impact on high-temperature char and G. Once the char was oxidized using a similar liquid oxidation method to prepare GO, the steam gasification rate of the oxidized Ca-added char presented higher reactivity at low temperature, which was similar to the gasification behavior of GO with calcium addition. Characterization results show that the oxygen-containing functional group of SL is similar to GO. By comparing the catalytic effect of calcium of oxidized char and GO with that of char and G, it was further demonstrated that the oxygen-containing functional group was the key structure for Ca-catalyzed coal gasification. These results suggest that GO is similar to SL not only in terms of its oxygen structure but also in its steam gasification reactivity. Thus, GO is an excellent model of lignite. This study provides a new lignite modeling approach with a more accurate structure than reported lignite models and is suitable for precise investigations of the structural evolution of lignite as well as the catalytic mechanism of calcium in steam gasification.

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“…The dried SL and SL ++ were also prepared similar to SL + . According to the previous results [ 31 ], the proximate and ultimate analyses of SL, SL + and SL ++ are listed in table 1 . Demineralized coal samples and mass fraction of the main metal elements are presented in table 2 .…”

Section: Methodsmentioning

confidence: 99%

The catalytic effect of calcium and potassium on CO ₂ gasification of Shengli lignite: the role of carboxyl

Ban¹,

Wang²,

Li³

et al. 2018

R. Soc. open sci.

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The CO2 gasification of Chinese Shengli lignite (SL) catalysed by K+ and Ca2+ was studied. The results showed that calcium could greatly decrease the gasification reaction temperature of SL, and the gasification reaction rates of acid-treated SL catalysed by calcium were significantly higher than that catalysed by potassium. Kinetic analysis showed that the activation energy of the reaction catalysed by calcium was much lower than that catalysed by potassium, which was the reason for the higher catalytic activity of calcium. Fourier transform infrared characterization showed that, compared with acid-treated SL, the addition of K+/Ca2+ resulted in the significant weakening of C=O bond, and new peaks attributed to carboxylate species appeared. X-ray photoelectron spectroscopy results indicated that the numbers of C=O decreased after the metal ions were added, indicating the formation of metal–carboxylate complexes. Raman characterization showed that the ID1/IG values increased, suggesting more structural defects, which indicated that the reactivity of coal samples had a close relation with amorphous carbon structures. Ca2+ could interact with the carboxyl structure in lignite by both ionic forces and polycarboxylic coordination, while K+ interacted with carboxyl structure mainly via ionic forces.

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Effect of inorganic acid elution on microcrystalline structure and spontaneous combustion tendency of Shengli lignite

Cited by 20 publications

References 20 publications

Occurrence Mechanism and Risk Assessment of Dynamic of Coal and Rock Disasters in the Low-Temperature Oxidation Process of a Coal-Bed Methane Reservoir

Occurrence Mechanism and Risk Assessment of Dynamic of Coal and Rock Disasters in the Low-Temperature Oxidation Process of a Coal-Bed Methane Reservoir

Graphite and Graphite Oxide: New Models to Analyze the Calcium Catalytic Effect on Steam Gasification of Lignite and Char

The catalytic effect of calcium and potassium on CO ₂ gasification of Shengli lignite: the role of carboxyl

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Effect of inorganic acid elution on microcrystalline structure and spontaneous combustion tendency of Shengli lignite

Cited by 20 publications

References 20 publications

Occurrence Mechanism and Risk Assessment of Dynamic of Coal and Rock Disasters in the Low-Temperature Oxidation Process of a Coal-Bed Methane Reservoir

Occurrence Mechanism and Risk Assessment of Dynamic of Coal and Rock Disasters in the Low-Temperature Oxidation Process of a Coal-Bed Methane Reservoir

Graphite and Graphite Oxide: New Models to Analyze the Calcium Catalytic Effect on Steam Gasification of Lignite and Char

The catalytic effect of calcium and potassium on CO 2 gasification of Shengli lignite: the role of carboxyl

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The catalytic effect of calcium and potassium on CO ₂ gasification of Shengli lignite: the role of carboxyl