Effect of particle size on indicator gas emission during high-temperature oxidation of weathered coal

2020 ◽  
Author(s):  
JiaJia Song ◽  
Jun Deng ◽  
JingYu Zhao
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Spontaneous Combustion ◽  
Combustion Characteristics ◽  
Particle Sizes ◽  
Gas Emission ◽  
Temperature Oxidation ◽  
Weathered Coal ◽  
Effect Of Particle Size

<p>Coal spontaneous combustion is one of the severe nature hazards among nature resources. There are many influence factors which control the development of spontaneous combustion such as particle size, oxygen concentration, etc. Weathering effects alter the spontaneous combustion characteristics of coal. To explore the effect of particle size on gas emission from weathered coal under high temperature oxygen deficiency, the macroscopic spontaneous combustion characteristics of weathered coal with various particle sizes in high temperature oxidation process were studied. The gas concentration of different particle sizes with weathered coal oxidation from normal temperature to 600 °C was tested by the self-built high temperature program experiment system, and the variation law of the indicator gas was analyzed. The results showed that there were different experimental phenomena in each particle size coal sample. The concentration of indicator gas neither increased nor decreased monotonically with the change of particle size. Roughly, 3 mm is the critical particle size in the process of high temperature oxidation of weathered coal. The experimental results provided a pivotal theoretical basis for the early prediction and the scientific prevention of the spontaneous combustion of the weathered coal during the mining process of the open pit and the shallow coal seam.</p>

Critical particle size analysis of gas emission under high-temperature oxidation of weathered coal

Energy ◽  
2021 ◽  
Vol 214 ◽  
pp. 118995 ◽  
Author(s):  
Jiajia Song ◽  
Jun Deng ◽  
Jingyu Zhao ◽  
Yanni Zhang ◽  
Caiping Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Gas Emission ◽  
Temperature Oxidation ◽  
Weathered Coal ◽  
Critical Particle Size

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.

Gases and thermal behavior during high-temperature oxidation of weathered coal

2019 ◽  
Vol 138 (2) ◽  
pp. 1573-1582 ◽  
Author(s):  
Jun Deng ◽  
Jia-Jia Song ◽  
Jing-Yu Zhao ◽  
Yan-Ni Zhang ◽  
Yu-Xuan Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Behavior ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
Weathered Coal

Thermogravimetric Study of the Effect of Particle Size on the Spontaneous Combustion of Indonesian Low Rank Coal

2013 ◽  
Vol 330 ◽  
pp. 101-105 ◽  
Author(s):  
Muksin Saleh ◽  
Yulianto Sulistyo Nugroho
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Spontaneous Combustion ◽  
Moisture Loss ◽  
Low Rank ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Isothermal Method ◽  
Size Groups ◽  
Effect Of Particle Size

Low-temperature oxidation of two Indonesian low rank coals was characterized by Thermogravimetric analysis (TGA). The effect of particle size on the spontaneous combustion of coal was examined. Coals were classified to-599+299, -299+249, -249-150, -150+76 and-76 μm size groups and through non-isothermal method scanned from 24 to 600°C at heating rate 5°C/min with air flow rate 50 mL/min. DTA thermogram shows that the transition temperatures decrease by decreasing the particle size. Furthermore, the weight loss increases by decreasing particle size. It is indicated that the propensity of coal to spontaneous combustion increase with decreasing particle size. The moisture loss activation energy and oxidation activation energy were calculated by an integral method using the Coats-Redfern formula. The results show that the propensity for spontaneous combustion of two coal samples (judged by the activation energy) increases by decreasing particle size.

Particle Size Effect on FeS Spontaneous Combustion Characters in Petroleum

2014 ◽  
Vol 608-609 ◽  
pp. 971-975
Author(s):  
Man Yang ◽  
Xian Feng Chen ◽  
Yu Jiao Shang ◽  
Ren Dong Bao
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Reaction Mechanisms ◽  
Spontaneous Combustion ◽  
Oxidation Kinetic ◽  
Mesh Size ◽  
Particle Size Effect ◽  
Particle Sizes ◽  
Heating Rates ◽  
Effect Of Particle Size

In order to evaluate the effect of particle size on FeS Spontaneous Combustion Characters, four different grain diameters of FeS particles (100, 170, 220, 320-mesh) were detected in the experiment. The reaction process at heating rates of 5°C /min in air flow from 30°C to 900°C were studied by TG-DSC and oxidation kinetic analysis. The activation energies of samples were calculated by the Coats-Redfern method. It is found that four reaction mechanisms are involved in FeS spontaneous combustion for different particle sizes; the activation energy values change from 307.4 to 398.05 kJ/mol; larger size particles have higher activation energy values; so grain diameters larger than 100-mesh size samples are less inclined to be oxidized and self-ignited.

Behaviour of copper during the high temperature oxidation of steels produced by the electric furnace route

2003 ◽  
Vol 100 (1) ◽  
pp. 73-82
Author(s):  
Y. Riquier ◽  
D. Lassance ◽  
I. Li ◽  
J. M. Detry ◽  
A. Hildenbrand
Keyword(s):  
High Temperature ◽  
Electric Furnace ◽  
High Temperature Oxidation ◽  
Temperature Oxidation
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