Erosion effect on microstructure change and oxidation behavior of long-flame coal under different pH conditions

Guo, Shengli; Yuan, Shujie; Geng, Weile; Dong, Ziwen

doi:10.1016/j.fuel.2021.120422

Cited by 32 publications

(8 citation statements)

References 45 publications

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“…Before the reaction between coal and oxygen, the content of CC in coal was stable. To ensure the relative consistency of the contents of the functional groups, the total peak area of CC functional groups was calculated, and the contents of different functional groups in the rest of the paper were the result of dividing the corresponding area by the peak area of the CC group. − The peak fitting results in the range of 1000–1800, 2300–3000, and 3000–3800 cm –1 for the four coal samples is shown in Figure b–d.…”

Section: Resultsmentioning

confidence: 99%

Influence of Long-Term Immersion in Water at Different Temperatures on Spontaneous Combustion Characteristics of Coal

Zhang,

Dong,

Kong

et al. 2023

ACS Omega

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The effect of hydrothermal coupling on the risk of spontaneous combustion of coal (SCC) soaked at different water temperatures was studied. The results showed that the porosity and permeability of coal increased significantly after immersion in water at different temperatures. The increase at a water temperature of 30 °C was the largest, the porosity was 22.77% higher, and the permeability was 3.44 times that of raw coal. The relative content of oxygen-containing functional groups, aliphatic functional groups, and hydroxyl functional groups reached 1.8−4.5, 1.1−4.4, and 0.7−1.48 times that of raw coal after soaking in water at different temperatures. The increase ratio of functional groups is the largest under the water temperature of 30 °C. The activation energy of coal samples soaked at water temperatures of 30 and 45 °C decreased by 9.4 and 2.9%, respectively. Under the condition that the coal sample temperature was lower than 110 °C, the highest oxygen consumption rate and heat release rate were coal samples soaked at water temperatures of 30 °C, and the lowest was raw coal. When the coal temperature was higher than 170 °C, all coal samples soaked in different water temperatures are higher than that of raw coal, and the water temperature of 30 °C is the highest. The risk of spontaneous combustion of coal is highest after long-term soaking at 30 °C water.

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Section: Resultsmentioning

confidence: 99%

Influence of Long-Term Immersion in Water at Different Temperatures on Spontaneous Combustion Characteristics of Coal

Zhang,

Dong,

Kong

et al. 2023

ACS Omega

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“…In recent years, many scholars have carried out studies on softening the coal body to relieve pressure, so as to reduce the impact of rock bursts in deep mines (Ni et al, 2019; Guerue et al,2008; Guo et al, 2021; Xu et al, 2021). Deep coal seams usually have obvious characteristics of high pressure, strong adsorption and low permeability (Zhou et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Desensitization effect of chemically induced coal components at room temperature: An experimental study

Chen³

et al. 2022

Energy Exploration & Exploitation

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This study was conducted to address the rock burst problem caused by serious stress concentrations in coal seams. Based on the principle of inducing agent corrosion affecting coal components to soften coal, different inducers were selected to study the desensitization effect of acid leaching induction on coal components. The microscopic behavior characteristics of coal under acid leaching were analyzed, and the qualitative and quantitative laws were obtained for different acid leaching times and microscopic behavior characteristics. The results show the following: (1) The mixed acid solution as an inducer has the effect of immersion, dissolution, and fracture on coal. During the reaction process, the internal pores of the coal expand, and the height of the external liquid decreases. The mixed acid solution had the best effect in terms of the removal of minerals in coal. (2) Under microscopic conditions, the internal crack width of the coal body expanded several times after mixed acid soaking; the difference in the unevenness before and after compression fracture was stable at 25–27%, and the mixed acid expanded the gap in the coal. (3) This practical study shows that the characterization changes of the mixed acid solution, injected into the borehole, combines the characteristics of the citric acid and phosphoric acid solution. The minerals around the borehole are dissolved, and the debris fuses with the solution. The liquid is viscous and forms a film on the surface of the solution. The mixed acid has a more obvious effect on the immersion and dissolution of coal.

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“… 34 Therefore, it is insufficient to use noncoal reference samples in the experiments of low-rank coal, especially for high-moisture-content coal. 35 , 36 …”

Section: Introductionmentioning

confidence: 99%

“…The change of the structure will significantly change the spontaneous combustion characteristics of coal. − With the decrease in the particle size, the moisture content, the heat of wetting release, and the risk of spontaneous combustion increase . Therefore, it is insufficient to use noncoal reference samples in the experiments of low-rank coal, especially for high-moisture-content coal. , …”

Section: Introductionmentioning

confidence: 99%

“…34 Therefore, it is insufficient to use noncoal reference samples in the experiments of lowrank coal, especially for high-moisture-content coal. 35,36 The existing experimental methods can reflect the process of coal spontaneous combustion to a certain extent and have a higher theoretical value, but they also have several shortcomings. The experimental process of a large-scale test bench is more complex and yields low precision and poor repeatability.…”

Section: Introductionmentioning

confidence: 99%

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Rapid Contrastive Experimental Study on the Adiabatic Spontaneous Combustion Period of Loose Lignite

et al. 2021

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The adiabatic spontaneous combustion period of coal is an important index for the macroscopic characterization of coal spontaneous combustion, and it is affected by many internal and external factors. There are several methods to study it, but there are various shortcomings to these methods. Some require too much time, while others have too many interfering factors. To quickly obtain the accurate adiabatic spontaneous combustion period of coal, a rapid contrastive experimental method was designed. In this method, the coal samples of the experimental and control groups were the same, and air and nitrogen were used as control atmospheres. A theoretical calculation method for the adiabatic spontaneous combustion period based on this method is proposed. The experimental results showed that during the temperature-programmed coal spontaneous combustion experiment, the increase in the coal temperature was due to physical and chemical heating. Physical heating is the heating effect of the temperature-programmed furnace body and the heated gas on the coal sample. Chemical heating includes oxidative exothermic heating promoted by physical and adiabatic oxidation heating. The adiabatic oxidative heat release can be determined by the oxidation heat release in the air atmosphere minus the oxidation heat release corresponding to the coal sample temperature in the nitrogen environment at the same period. The adiabatic spontaneous combustion period of coal can be calculated from the adiabatic oxidation heat release. Our results provide a rapid contrastive experimental method to quickly obtain the accurate adiabatic spontaneous combustion period of coal.

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Erosion effect on microstructure change and oxidation behavior of long-flame coal under different pH conditions

Cited by 32 publications

References 45 publications

Influence of Long-Term Immersion in Water at Different Temperatures on Spontaneous Combustion Characteristics of Coal

Influence of Long-Term Immersion in Water at Different Temperatures on Spontaneous Combustion Characteristics of Coal

Desensitization effect of chemically induced coal components at room temperature: An experimental study

Rapid Contrastive Experimental Study on the Adiabatic Spontaneous Combustion Period of Loose Lignite

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