A new numerical method to predict the growth temperature of spontaneous combustion of 1/3 coking coal

Xiao, Yang; Lü, Hui-Fei; Huang, An‐Chi; Deng, Jun; Shu, Chi‐Min

doi:10.1016/j.applthermaleng.2017.12.007

Cited by 33 publications

(8 citation statements)

References 33 publications

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“…In partial reaction 1 , the burning of numerous volatile matter and fixed carbon released a large amount of heat and various gaseous products, meanwhile accompanied by the burning of char at a higher temperature, whereas partial reaction 2 was mainly related to the combustion of small amounts of char and pyrolysis of mineral components, which led to a further tiny mass loss (as shown in Table 2 ). 30 …”

Section: Resultsmentioning

confidence: 99%

Comparative Analyses between Raw and Preoxidized Pulverized Coals: Combustion Behaviors and Thermokinetic and Microcharacteristics

et al. 2021

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Investigating the difference in the combustion performance and microcharacteristics of oxidized and raw pulverized coal (PC) can contribute to effectively prevent and control the spontaneous combustion of deposited coal dust in high-temperature environment and further help guarantee the safe operation of coal-fired boiler. In this study, the combustion performance and thermokinetic and microcharacteristics of three raw coal samples and their preoxidized forms were explored by a thermogravimetric analyzer (TGA) and Fourier transform infrared spectroscopy (FTIR). According to the characteristic temperatures and variations of the mass loss rate during heating, the entire combustion process of PC was divided into four periods. For each type of coal, the preoxidized PC had relatively lower characteristic temperatures than the corresponding raw PC. The preoxidized samples had larger values of ignition index ( C ig ) and comprehensive combustibility index ( S ), but lower values of burnout index ( C b ) than raw samples. The values of apparent activation energy ( E ) for the preoxidized PC were below that of the corresponding raw PC at the same conversion rate (α), which suggested the preoxidized PC required relatively less energy to react and was more prone to spontaneous combustion. In addition, although parts of −OH, C=O, and aliphatic hydrocarbon groups were consumed after the preoxidation treatment, the increase in C–O and −COO– bonds compensated for the adverse effect of the reduction of the aforementioned groups on coal combustion.

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Section: Resultsmentioning

confidence: 99%

Comparative Analyses between Raw and Preoxidized Pulverized Coals: Combustion Behaviors and Thermokinetic and Microcharacteristics

et al. 2021

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Section: Introductionmentioning

confidence: 99%

“…Therefore, studying the hydrophilic capacity of 1/3 coking coal has an essential supporting role, which can provide a certain theoretical basis for hydraulic and efficient gas extraction. 10 Currently, coal−water adsorption systems have been studied more experimentally, but the properties of hydration films formed by water molecules after immersion into coal molecules cannot be obtained from the microscopic perspective, 11,12 which is only elaborated from the perspective of the interaction between coal and water molecules via molecular dynamic simulation methods, ignoring the structure of the functional groups contained in coal molecules. 13−16 In contrast, Fourier transform infrared spectroscopy (FT-IR) provides insights on the functional groups.…”

Section: Introductionmentioning

confidence: 99%

“…Through high-pressure water injection in coal mine, hydration films will be formed on the surface of the 1/3 coking coal matrix in order to reduce gas adsorption capacity, replace gas, and improve the extraction rate. Therefore, studying the hydrophilic capacity of 1/3 coking coal has an essential supporting role, which can provide a certain theoretical basis for hydraulic and efficient gas extraction …”

Section: Introductionmentioning

confidence: 99%

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Dynamic Simulation Based on a Simplified Model of 1/3 Coking Coal Molecule and Its Formation Characteristics of Hydration Films

Zhu

Zhang

et al. 2021

ACS Omega

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To comprehensively elaborate the formation characteristics of hydration films on 1/3 coking coal molecule, this paper reports the construction of a realistic simplified model for calculations of electrostatic potentials on the coal molecular surface to foresee the major immersion locations. On this basis, interactions at the interface of coal molecules with different numbers of water molecules and their effects on each functional group of coal molecules were investigated. Using the scanning electron microscopy experiment, changes in the coal matrix before and after water leaching were compared and analyzed by fractal dimension calculations. Hydration characteristics of coal were described from a combined macroscopic and microscopic perspective. The results showed that both positive and negative electrostatic potential of coal molecules occurred near the O-containing functional groups. The hydroxyl group’s electrostatic potential (−OH) rose, resulting in higher electrostatic potential in coal–water molecules and providing many immersion sites. Deficiency in water molecules led to the complete immersion of water molecules. The interface of coal molecules could not be covered entirely, which led to the low number of active sites and Z values. The interface of coal–water molecules did not affect the average bond lengths of water molecules but decreased the bond angle by 3–4°. The influence ofwater molecules on the −OH groups of coal molecules was the most prominent when water molecules were incorporated into the coal molecules. Water damage for the coal matrix is more pronounced than in the raw coal itself. In view of above research, the formation characteristics of the hydration film from a microscopic point of view explained that the initial hydration of coal molecules was owing to H-bonds. From a macroscopic perspective, it was mainly due to structure changes for the coal matrix. This provides valuable references for field experiments in hydraulic fracturing and perforation.

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“…After the coal in the goaf is immersed in moisture, coal may gradually reduce the moisture due to the influence of long-term air leakage. In these environments, some coals will be in the low moisture content state [8] (low moisture content of coal, Mt ≤ 8.0%, according to China Coal Water Classification Industry Standards, MT/T 850-2000) due to the external environment, once spontaneous combustion of coal occurs, it not only will inevitably cause coal resources waste, environmental pollution, and severe economic losses, but also directly endangers the safety of field workers [9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Study on Spontaneous Combustion Tendency of Coals with Different Metamorphic Grade at Low Moisture Content Based on TPO-DSC

Fan¹,

Wang²,

Zhang³

2019

Preprint

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In the environments of all kinds open coal storage sites , mining-affected coalbeds, and goafs, parts of coal body at low moisture content (≤8%) are prone to spontaneous combustion under the influence of some external environmental factors. In order to examine the influence effect of low moisture content on the spontaneous combustion tendency of coals with different metamorphic grade, we conducted temperature programmed oxidation (TPO) experiment and differential scanning calorimetry (DSC) experiment to study the spontaneous combustion characteristics of coals with different metamorphic grade at four different low moisture content, and comparatively analyzed the change laws of the characteristic parameters of four different metamorphic grade coals at four different low moisture content. The experimental results indicate that: 1) Compared other low moisture content, anthracite and fat coal at low moisture content of 1.2% show stronger tendency to undergo spontaneous combustion, long flame coal and lignite at low moisture content of 3.4% and 5.6% are more prone to spontaneous combustion. 2) Four different metamorphic grade coals at low moisture content of 7.8% are less prone to spontaneous combustion; 3) Coals with different metamorphic grade have different tendency to undergo spontaneous combustion.

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A new numerical method to predict the growth temperature of spontaneous combustion of 1/3 coking coal

Cited by 33 publications

References 33 publications

Comparative Analyses between Raw and Preoxidized Pulverized Coals: Combustion Behaviors and Thermokinetic and Microcharacteristics

Comparative Analyses between Raw and Preoxidized Pulverized Coals: Combustion Behaviors and Thermokinetic and Microcharacteristics

Dynamic Simulation Based on a Simplified Model of 1/3 Coking Coal Molecule and Its Formation Characteristics of Hydration Films

Study on Spontaneous Combustion Tendency of Coals with Different Metamorphic Grade at Low Moisture Content Based on TPO-DSC

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