Comprehensive and Dynamic Cooling Technology of High-Temperature Working Face with Multiple Heat Sources in Coal Seam Prone to Spontaneous Combustion

2021 ◽  
Author(s):  
Hongbin Zhao ◽  
Shihao Tu ◽  
Xun Liu ◽  
Jieyang Ma ◽  
Long Tang
Keyword(s):  
High Temperature ◽  
Coal Seam ◽  
Spontaneous Combustion ◽  
Heat Sources ◽  
Working Face ◽  
Dynamic Cooling ◽  
Cooling Technology

scholarly journals Investigation of the kinetics of spontaneous combustion of the major coal seam in Dahuangshan mining area of the Southern Junggar coalfield, Xinjiang, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li Shen ◽  
Qiang Zeng
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Coal Seam ◽  
Spontaneous Combustion ◽  
Heating Temperature ◽  
Characteristic Temperature ◽  
Mining Area ◽  
Particle Sizes ◽  
Coal Oxidation ◽  
Increasing Temperature

AbstractIn the present paper, with using diverse methods (including the SEM, the XRD, the TPO, the FTIR, and the TGA) , the authors analysed samples of the major coal seam in Dahuangshan Mining area with different particle sizes and with different heated temperatures (from 50 to 800 °C at regular intervals of 50 °C). The results from SEM and XRD showed that high temperature and high number of pores, fissures, and hierarchical structures in the coal samples could facilitate oxidation reactions and spontaneous combustion. A higher degree of graphitization and much greater number of aromatic microcrystalline structures facilitated spontaneous combustion. The results from TPO showed that the oxygen consumption rate of the coal samples increased exponentially with increasing temperature. The generation rates of different gases indicated that temperatures of 90 °C or 130 °C could accelerate coal oxidation. With increasing temperature, the coal oxidation rate increased, and the release of gaseous products was accelerated. The FTIR results showed that the amount of hydroxide radicals and oxygen-containing functional groups increased with the decline in particle size, indicating that a smaller particle size may facilitate the oxidation reaction and spontaneous combustion of coal. The absorbance and the functional group areas at different particle sizes were consistent with those of the heated coal samples, which decreased as the temperature rose. The results from TGA showed that the characteristic temperature T3 declined with decreasing particle size. After the sample with 0.15–0.18 mm particle size was heated, its carbon content decreased, and its mineral content increased, inhibiting coal oxidation. This result also shows that the activation energy of the heated samples tended to increase at the stage of high-temperature combustion with increasing heating temperature.

scholarly journals The Influence of the Sample Preparation on the Result of Coal Propensity to Spontaneous Combustion in the High-temperature Adiabatic Method

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Dariusz OBRACAJ ◽  
Marek KORZEC ◽  
Tien Tung VU
Keyword(s):  
High Temperature ◽  
Coal Seam ◽  
Spontaneous Combustion ◽  
Spontaneous Heating ◽  
Mine Fire ◽  
Mine Fires ◽  
Technical Factors ◽  
Spontaneous Combustion Of Coal ◽  
Seam Mining ◽  
Very High

The liability of coal to spontaneous combustion is the principal cause of mine fires. Spontaneouscombustion is one of the main threats in Polish and Vietnamese coal mines. The article presents an analysisof the spontaneous combustion of coal in mines of both countries. It is related to the natural prone of coalto spontaneous heating and consequently to its self-ignition. Despite the relevant recognition of themethods of preventing this threat, in mines, spontaneous combustion occurs during the exploitation ofcoal seams with low and very high self-ignition tendency. Apart from the technical factors related to thedesign of coal seam mining, the properties of coal have a significant impact on the occurrence ofspontaneous combustion. Their correct recognition is essential to the precautions against spontaneouscombustion for minimalizing the risk of a mine fire. Therefore, it is necessary to study the factorsinfluencing the propensity of coal to spontaneous heating. A review of the methods used to determine thepropensity of coal to spontaneous combustion is presented in the article. Based on the high-temperaturemethod of determining the propensity of coals to spontaneous combustion, the influence of selectedfactors related to samples' preparation for testing on the determination result was investigated. Theinfluence of the fractional decomposition and the moisture content in the prepared samples on thedetermination result was demonstrated. The presented research results may improve research proceduresfor determining the propensity of coal to spontaneous combustion.

Spontaneous Combustion Characteristics and Air Leakage Control Technology of Half Isolated Island Fully Mechanized Caving Face

2013 ◽  
Vol 718-720 ◽  
pp. 1639-1644 ◽  
Author(s):  
Yu Bing Mu
Keyword(s):  
High Temperature ◽  
Spontaneous Combustion ◽  
Coal Pillar ◽  
Combustion Characteristics ◽  
Air Leakage ◽  
Tracer Gas ◽  
Danger Zone ◽  
Working Face ◽  
High Temperature Area ◽  
Safe Mining

The 3-105 half isolated island fully mechanized caving face in Tengdong coal mine which in complex geological and high temperature condition, has a spontaneous combustion feature that is different from normal advancing mechanized caving face, such as slowly advance speed, stress concentration and air leakage of inside-impending gob. To overcome the dangerous possibility of spontaneous combustion between the roof coal seam inside-impending gobs, small coal pillar and adjacent gob of half isolated island fully mechanized caving face, analysis spatial structure of overlying strata roof and spontaneous combustion characteristics. Based on the result of pressure can be measured and tracer gas test of air leakage channels, determine the potential air leakage areas. The MEA plugging wind material is pumped into roadway and SPA-4 plugging wind material is spray around known air leakage or high temperature area to eliminate the hazards of spontaneous combustion of the potential danger zone, and protects the safe mining of the working face.

Inverse Arithmetic of the Equivalent Heat Transfer Coefficient of Mine Goaf

2011 ◽  
Vol 328-330 ◽  
pp. 1013-1016
Author(s):  
Shuai Heng ◽  
Feng Gao ◽  
Xing Guang Liu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
High Temperature ◽  
Transfer Coefficient ◽  
Measured Data ◽  
Heat Sources ◽  
Calculating Method ◽  
Temperature Forecast ◽  
Working Face ◽  
Conservation Of Momentum

In order to calculate the dissipating capacity of heat sources and improve the veracity of airflow temperature forecast of mine, the equivalent heat transfer coefficient of mine goaf was calculated by means of inverse arithmetic based on the law of conservation of momentum and measured data from a high temperature working face. The results of calculation show that the equivalent heat transfer coefficient of mine goaf can reflect the heat dissipating characteristics generally and reduce the calculating method of the heat dissipating capacity of mine goaf, then it can be used better in the airflow temperature forecast.

Simulation on Parameters Temperature Field by Gas-Solid Coupling in Goaf

2012 ◽  
Vol 229-231 ◽  
pp. 1815-1818
Author(s):  
Yue Hong Wang ◽  
Yue Ping Qin ◽  
Jiu Ling Zhang ◽  
Jia Li Wen
Keyword(s):  
Temperature Field ◽  
High Temperature ◽  
Temperature Region ◽  
High Efficiency ◽  
Spontaneous Combustion ◽  
Linear Increase ◽  
High Temperature Region ◽  
Working Face ◽  
Volume Method ◽  
Relationship Of

For solution the complex and rapidly changing question of temperature field in mining goaf, the simulation on dynamic temperature field of parameters coupling is carried out under different working coditions based on high-efficiency finite volume method (FVM) and the moving characteristic of working face. The theory analysis, the laboratory experiment, the simulation of software and the example confirmation, above all methods are used in order to find the change of temperature field in goaf. The result is found that there has spontaneous combustion in goaf when the moving speed of working face is below 1.2m/d; besides that the temperature in goaf fall and the high-temperature region is extend to the deep of goaf. Another result is exist that there has the linear increase relationship of the intensity of leak air and the temperature in goaf, and the high-temperature region is extend to the deep of goaf contrary to the effect of the coal oxidation properties, which increases the risk of coal spontaneous combustion in goaf. Especially , all the data of temperature is visualization by picture of 3D, so the distribution map of temperature in goaf is visualized distinctly. The research results provide a theoretical basis for understanding the real situation and preventing spontaneous combustion in goaf.

scholarly journals Optimization of Barrier Pillar Design in Longwall Mining with Top Coal Caving in Spontaneous Combustion Coal Seam

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Qiang Fu ◽  
Ke Yang ◽  
Qinjie Liu ◽  
Shuai Liu ◽  
Xiang He ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Coal Seam ◽  
Spontaneous Combustion ◽  
Longwall Mining ◽  
Volume Fraction ◽  
Coal Pillar ◽  
Adjacent Area ◽  
Maximum Displacement ◽  
Working Face ◽  
Barrier Pillar

Determining a reasonable barrier pillar along gob-side entry of spontaneous combustion coal seam is of great significance to the prevention of spontaneous combustion. In this paper, considering the actual situation of 4301 and 4302 working faces of II-class spontaneous combustion coal seam in Changheng Mine, the characteristics of rock mass collapse and mining-induced stress redistribution of barrier pillar and adjacent area were analyzed, the cusp catastrophe model of coal pillar instability and the theoretical model of limit width of coal pillar air leakage spontaneous combustion were established, and a measurement scheme of side abutment pressure in 4301 working face was carried out. The theoretical model of the coal pillar along the gob-side entry shows that its instability is related to density of overlying strata, physical and mechanical parameters of coal body, dip angle of coal seam and weak face, and buried depth and mining width of working face. And the coal pillar in 4302 working face will be unstable if the width a ≤ 6.8   m . Field measured data shows that 2-8 m is the stress-relaxation area of side solid coal. Then, the width of coal pillar was determined as 7 m. The maximum displacement of rib-to-rib and roof-to-floor of 4302 tailentry was 520 mm and 280 mm, respectively. The coal spontaneous combustion (CSC) observation monitoring results showed that the carbon monoxide volume fraction was in the normal range during the entire process of mining, and no other signs of gas were found. The research results can provide a reference for the barrier pillar designing in the mines under similar conditions.

Study on infrared detection of coal seam spontaneous combustion high temperature anomaly area

2021 ◽  
Author(s):  
Linchao Shi ◽  
Xiangyang Zhang ◽  
Biao Kong ◽  
Angling Ren ◽  
Linxuan Li ◽  
...  
Keyword(s):  
High Temperature ◽  
Coal Seam ◽  
Spontaneous Combustion ◽  
Temperature Anomaly ◽  
Infrared Detection
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