Changes in spontaneous combustion characteristics of low-rank coal through pre-oxidation at low temperatures

Jo, Wantaek; Choi, Hokyung; Kim, Sang-Do; Yoo, Jiho; Chun, Dong Hyun; Rhim, Youngjoon; Lim, Jeong-Hoon; Lee, Sihyun

doi:10.1007/s11814-014-0228-7

Cited by 35 publications

(13 citation statements)

References 19 publications

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“…The shape of the air flow transport route is similar to the letter "U," which is called "U" ventilation system. [23][24][25][26][27][28][29] For a long time, most scholars have studied the "three zones of spontaneous combustion" in association with a "U" ventilation system. The shape of the air flow transport route is similar to the letter "Y," which is called "Y" ventilation system.…”

Section: Coal Enterprises In Chinamentioning

confidence: 99%

“…To study the problem of fire prevention and extinguishing under the condition of non-pillar coal mining technology, especially the coal spontaneous combustion mechanism, scholars have conducted considerable studies. [23][24][25][26][27][28][29] For a long time, most scholars have studied the "three zones of spontaneous combustion" in association with a "U" ventilation system. 30 Generally, the gas pressure in goaf of "U" ventilation system is fan-shaped distribution with the center of the intersection of working face and air inlet and air return way.…”

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confidence: 99%

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Evolution characteristics of spontaneous combustion in three zones of the goaf when using the cutting roof and release pressure technique

Chen

Guo³

et al. 2019

Energy Science & Engineering

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The changes associated with the cutting roof and release pressure mining method in the three zones that are susceptible to spontaneous combustion in the goaf with “Y” type ventilation system were studied. For the investigated underground coal mine working face, its three zones of spontaneous combustion have a “U” type ventilation system for the traditional mining method and a “Y” type ventilation system for the cutting roof and release pressure mining method. These systems were monitored using a beam tube method, and the evolution characteristics of spontaneous combustion of the three zones was analysed. The monitoring data showed that when using a traditional mining method with a “U” type ventilation system, the scattered tropical zone converts into the oxidation heating zone after 68.5 m in the goaf, and the suffocative zone presents after 85.5 m. For the cutting roof and release pressure mining method together with a “Y” type ventilation system, the scattered tropical zone converts into the oxidation heating zone after 84 m in the goaf, and the suffocative zone appears after 198.8 m. Compared to traditional mining, the width of the oxidation heating zone increases when using the cutting roof and release pressure method. To prevent spontaneous combustion of the goaf, the comprehensive techniques of the pressure balance for fire control, ground fissure sealing, working face sealing, retained roadways guniting and inert gas fire extinguishing have been used in the studied coal mine. The CO concentration of the goaf is less than 300 ppm during the mining process. Safe mining of the tested working face shows that the cutting roof and release pressure technique can be applied to control the coal seam spontaneous combustion.

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Section: Coal Enterprises In Chinamentioning

confidence: 99%

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confidence: 99%

Evolution characteristics of spontaneous combustion in three zones of the goaf when using the cutting roof and release pressure technique

Chen

Guo³

et al. 2019

Energy Science & Engineering

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“…Correlation coefficient (dimensionless) O daf O content of air-dried basis (%) S daf S content of air-dried basis (%) T Thermokinetic temperature (K) T 1 First characteristic temperature, critical temperature (°C) T 2 Second characteristic temperature, active temperature (°C) T 3 Third characteristic temperature, pyrolysis temperature (°C) T 4 Fourth characteristic temperature, ignition temperature (°C) T 5 Fifth characteristic temperature, burned-out temperature (°C)…”

Section: List Of Symbolsmentioning

confidence: 99%

“…China is the largest coal-producing country [3,4], and the problem of coal spontaneous combustion [5][6][7] is gaining increasing attention. To govern the wastage of coal resources, numerous coal mines in China have begun to re-mine old coal mines and mined-out areas, which have a risk of second or multiple oxidations.…”

Section: Introductionmentioning

confidence: 99%

Thermal behavior and microcharacterization analysis of second-oxidized coal

Deng

Zhao

Huang

et al. 2016

J Therm Anal Calorim

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Among coal-producing countries, China has witnessed the highest frequency and severity of coal fires. During mining in the re-mining face and the lower part of the thick coal seam (or coal seam group), second or multiple oxidations of the residual coal can readily occur in mined-out areas, severely increasing the risk of coal fires. The study of multiple oxidations of coal aids in the early detection of spontaneous combustion of remaining coal in the mined-out areas. The characteristics of coal fires are demonstrated using fresh coal samples (first-oxidized coal) and oxidized coal samples (second-oxidized coal) from four different ranks of coals. Proximate and elemental analysis, Fourier transform spectroscopy, and thermogravimetry-differential scanning calorimetry were adopted to investigate the quality, microcharacteristics, characteristic temperatures, and apparent activation energy of second-oxidized coal. In addition, the effect of spontaneous combustion at heating rates of 5.0, 10.0, and 15.0°C min -1 was studied. Compared with the four samples of first-oxidized coal, those of second-oxidized coals cause fire easily under the same conditions. List of symbolsA, A k Pre-exponential factor (s -1 ) A ad Ash content in air-dried basis (%) bHeating rate (°C min -1 ) C daf C content of air-dried basis (%) da/dt Conversion rate (s -1 ) E a , E k Apparent activation energy (kJ mol -1 ) f(a)Function of degree of conversion (dimensionless) H daf H content of air-dried basis (%) M ad Moisture in air-dried basis (%) N daf N content of air-dried basis (%) R Universal gas constant (8.314 J mol -1 K -1 ) r Correlation coefficient (dimensionless) O daf O content of air-dried basis (%) S daf S content of air-dried basis (%) T Thermokinetic temperature (K) T 1 First characteristic temperature, critical temperature (°C) T 2 Second characteristic temperature, active temperature (°C) T 3 Third characteristic temperature, pyrolysis temperature (°C) T 4 Fourth characteristic temperature, ignition temperature (°C) T 5 Fifth characteristic temperature, burned-out temperature (°C)

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“…Lu et al analyzed the compositions and amounts of gases generated by the oxidation of various coal samples over various temperature ranges and established quantitative relationships between gas makers and temperature. Jo et al oxidized coal samples of various types and particle sizes via preheating and examined their susceptibility to spontaneous combustion. In view of the problems of abnormal gas outbursts and local gas accumulation in coal mines, Wang et al studied the effects of various gas concentrations on the spontaneous combustion properties of coal samples.…”

Section: Introductionmentioning

confidence: 99%

Micromechanism of spontaneous combustion and oxidation of an unloaded coal under repeated disturbance

Pan

et al. 2018

Int J Energy Res

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Summary This study presents an analysis of the effects of repeated disturbance on the spontaneous combustion and oxidation properties of coal masses that are encountered in deep mining. Raw coal samples were tested under temperature‐programmed and repeated loading‐unloading (LU) conditions. In addition, the infrared (IR) spectra of the coal samples subjected to repeated LU cycles (LU coal samples) were analyzed using OMNIC IR analysis software. The results show the following. The LU coal samples were more prone to oxidation than the original coal sample. As the number of LU cycles increased, the degree of oxidation of the coal gradually increased.

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Changes in spontaneous combustion characteristics of low-rank coal through pre-oxidation at low temperatures

Cited by 35 publications

References 19 publications

Evolution characteristics of spontaneous combustion in three zones of the goaf when using the cutting roof and release pressure technique

Evolution characteristics of spontaneous combustion in three zones of the goaf when using the cutting roof and release pressure technique

Thermal behavior and microcharacterization analysis of second-oxidized coal

Micromechanism of spontaneous combustion and oxidation of an unloaded coal under repeated disturbance

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