scholarly journals Temperature Variation on Coal Gangue Dumps under the Action of Heat Pipe: Case Study on Yinying Coal Mine in China

2021 ◽  
Author(s):  
Na Zhao ◽  
Yongbo Zhang ◽  
Jinrong Niu ◽  
Tong Gao ◽  
Zhigang Wang ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Temperature Variation ◽  
Coal Mine ◽  
Spontaneous Combustion ◽  
Internal Heat ◽  
Mining Area ◽  
Substantial Effect ◽  
Coal Gangue ◽  
Effective Control ◽  
Control Group

Abstract Coal gangue in long-term accumulation will often appear spontaneous combustion phenomenon. Generally, the disaster caused by it has always been one of the serious problems threatening the health of residents in the mining area. Master the regularity of deep temperature distribution and eliminate the internal heat is an effective method to control the spontaneous combustion. In this study, using the self-developed heat pipe (HP) and intelligent cloud monitoring software, three groups of single pipe experiments were carried out in different temperature areas of the coal gangue dump in Yinying Coal Mine, to analyze the internal temperature variation under the action of HP. The results show that the temperature is obviously restrained by the HP, and the average cooling range reaches 21.44% within 700h. However, the temperature of the control group without HP continued to rise by 8%. In the three groups of experiments, the effective control radius of single HP is 3m. When the depth of gangue is 1 ~ 4m and the temperature between 90 ℃ ~ 450 ℃, the cooling effect is the best. It revealed that the HP had a substantial effect on thermal removal and inhibited spontaneous coal gangue combustion. In addition, this paper provides a theoretical basis for the HP treatment of spontaneous combustion coal gangue dumps technology.

scholarly journals Environment influences and extinguish technology of spontaneous combustion of coal gangue heap of Baijigou coal mine in China

2017 ◽  
Vol 136 ◽  
pp. 66-72 ◽  
Author(s):  
Xiaowei Zhai ◽  
Shibo Wu ◽  
Kai Wang ◽  
Carsten Drebenstedt ◽  
Jingyu Zhao
Keyword(s):  
Coal Mine ◽  
Spontaneous Combustion ◽  
Coal Gangue ◽  
Spontaneous Combustion Of Coal

Effect Analysis of Nitrogen Injection on the Variation of “Oxidation Zone” in Coal Mine Gob Based on Numerical Simulation

2016 ◽  
Vol 9 (1) ◽  
pp. 47-54
Author(s):  
Jing Shen ◽  
Mingran Chang
Keyword(s):  
Numerical Simulation ◽  
Coal Mine ◽  
Heat Dissipation ◽  
Spontaneous Combustion ◽  
Oxidation Zone ◽  
Effect Analysis ◽  
Mine Fire ◽  
Nitrogen Injection ◽  
The Difference ◽  
Residual Coal

One of the main reasons for coal mine fire is spontaneous combustion of residual coal in gob. As the difference of compaction degree of coal and rock, the underground gob can be considered as a porous medium and divided into “three zones” in accordance with the criteria. The “three zones” are “heat dissipation zone”, “oxidation zone” and “choking zone”, respectively. Temperature programming experiments are taken and numerical simulation with obtained experimental data is utilized to analyze the distribution of “three zones” in this paper. Different width and depth of “oxidation zone” are obtained when the inlet air velocity is changed. As the nitrogen injection has inhibition effect on spontaneous combustion of residual coal in gob, nitrogen is injected into the gob. The widths of “oxidation zone” are compared before and after nitrogen injection. And ultimately the optimum location and volume of nitrogen injection are found out.

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 Simulating Heat Stress of Coal Gangue Spontaneous Combustion on Vegetation Using Alfalfa Leaf Water Content Spectral Features as Indicators

2021 ◽  
Vol 13 (13) ◽  
pp. 2634
Author(s):  
Qiyuan Wang ◽  
Yanling Zhao ◽  
Feifei Yang ◽  
Tao Liu ◽  
Wu Xiao ◽  
...  
Keyword(s):  
Heat Stress ◽  
Water Content ◽  
Spontaneous Combustion ◽  
Leaf Water ◽  
Coal Gangue ◽  
Leaf Water Content ◽  
Spectral Features ◽  
Lasso Regression ◽  
Stress Assessment ◽  
First Derivative

Vegetation heat-stress assessment in the reclamation areas of coal gangue dumps is of great significance in controlling spontaneous combustion; through a temperature gradient experiment, we collected leaf spectra and water content data on alfalfa. We then obtained the optimal spectral features of appropriate leaf water content indicators through time series analysis, correlation analysis, and Lasso regression analysis. A spectral feature-based long short-term memory (SF-LSTM) model is proposed to estimate alfalfa’s heat stress level; the live fuel moisture content (LFMC) varies significantly with time and has high regularity. Correlation analysis of the raw spectrum, first-derivative spectrum, spectral reflectance indices, and leaf water content data shows that LFMC and spectral data were the most strongly correlated. Combined with Lasso regression analysis, the optimal spectral features were the first-derivative spectral value at 1661 nm (abbreviated as FDS (1661)), RVI (1525,1771), DVI (1412,740), and NDVI (1447,1803). When the classification strategies were divided into three categories and the time sequence length of the spectral features was set to five consecutive monitoring dates, the SF-LSTM model had the highest accuracy in estimating the heat stress level in alfalfa; the results provide an important theoretical basis and technical support for vegetation heat-stress assessment in coal gangue dump reclamation areas.

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