scholarly journals Experimental Study on the Inhibition Effects of Nitrogen and Carbon Dioxide on Coal Spontaneous Combustion

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5256
Author(s):  
Yi Zhang ◽  
Jun Xu ◽  
Deming Wang
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Spontaneous Combustion ◽  
Inert Gases ◽  
Coal Spontaneous Combustion ◽  
Inhibition Effect ◽  
Burn Out ◽  
O2 Concentration ◽  
Temperature Combustion ◽  
High Temperature Combustion

Inert gases can effectively inhibit coal spontaneous combustion. In this paper, the inhibition effect of inert gases (N2 and CO2) on coal spontaneous combustion was studied. In the low-temperature oxidation stage, the constant-temperature heat release and apparent activation energy of coal sample were measured and calculated by the C80 micro-calorimeter. In the high-temperature combustion stage, the critical temperature, maximum peak temperature, ignition temperature, and burn-out temperature of coal samples were analyzed by the synchronous thermal analyzer. The results demonstrate that with the decrease of O2 concentration, the oxidation heat release of coal samples drops gradually while the apparent activation energy increases gradually. In the N2 and CO2 atmospheres, as the O2 concentration is reduced to 1.5% and 3%, respectively, the value of apparent activation energy changes from negative to positive, and the spontaneous reaction transits to a nonspontaneous reaction. The TG-DTG (thermogravimetric-derivative thermogravimetric) curve of coal sample in the high-temperature combustion stage indicates that the critical temperature exhibits a W-shaped trend with the decrease of O2 concentration, which also leads to gradual increases of maximum peak temperature, ignition temperature, and burn-out temperature. The above results signify that increasing the inert gas concentration can gradually reduce the oxidation and combustion rate and improve the inhibition effect on coal spontaneous combustion. In addition, when the O2 concentration is the same, the inhibition effect of CO2 on coal spontaneous combustion is superior to that of N2.

Effect of Hydrogen Bonds to Form Complexes for N Active Structures which Contained in Coal and the Ca-Based Inhibitor

2014 ◽  
Vol 881-883 ◽  
pp. 118-121 ◽  
Author(s):  
Chao Yu Hao ◽  
Qing Biao Zhao ◽  
Ji Ren Wang ◽  
Gui Long Chi
Keyword(s):  
Hydrogen Bonds ◽  
Spontaneous Combustion ◽  
Ring Structure ◽  
Quantum Chemistry Calculation ◽  
Coal Spontaneous Combustion ◽  
Geometrical Structures ◽  
Inhibition Effect ◽  
Active Structures ◽  
Chemistry Calculation ◽  
Formation Of Complexes

Based on the theory of coordinate inhibition three nitrogen-containing active structures of different aromatic in coal were established. Using quantum chemistry calculation method, the effect of hydrogen bonding on the formation of complexes that formed by three nitrogen-containing active structures of different aromatic and inhibitor were calculated in B3LYP/6-311G* levels. The results show that hydrogen bond can make H2O participation in forming complexes which formed by three nitrogen-containing active structures of different aromatic and metal ions. Hydrogen bonds play a molecular recognition and guiding role in the process of H2O involved in the formation of complexes. After H2O participating ligand through hydrogen bonds, the complexes formed Ca-O-H-O four-membered ring structure in the geometrical structures. It Shows that its stability are improved and not easy to contacts with O or reacting. It making coal spontaneous combustion can be well inhibition. After H2O participating ligand, aromatic change had little effect in stability of the complexes. It shows that different ranks of coal can get better inhibition effect after H2O participating ligand.

The Research on the Relationship between the Coal Volatile and the Kinetics Parameters by Thermo-Gravimetric Experiment

2012 ◽  
Vol 512-515 ◽  
pp. 1813-1818
Author(s):  
Li Na Qu ◽  
Yuan Gang Jiang ◽  
Ru Le Gao
Keyword(s):  
Activation Energy ◽  
Coal Combustion ◽  
Spontaneous Combustion ◽  
Volatile Matter ◽  
Coal Spontaneous Combustion ◽  
Thermo Gravimetric ◽  
Kinetics Parameters ◽  
Exponential Factor ◽  
Internal Mechanism ◽  
The Relationship

Coal spontaneous combustion is a common coal mine disaster, the internal mechanism of coal combustion is revealed better by researched the relationship between the coal volatile and the kinetics parameters. Based on the method of non-isothermal, the coal samples from Jinggezhuang9#, Jinggezhuang11#, Qianjiaying, Tangshan and Tunlan are used the thermo-gravimetric experiment. The relationship between the reactive kinetic parameter and the volatile matter are fond out, when the heating rate is 100C/min. The experiment results illustrate that the more the volatile matter is, the less the activation energy (E) and the Pre Exponential factor (A) are, and the difficulty rank of coal samples of spontaneous combustion is Jinggezhuang9#, Jinggezhuang11#, Tangshan, Qianjiaying, Tunlan.

Reactions of thiyl radicals. II. The photolysis of methyl disulfide vapor

1967 ◽  
Vol 45 (12) ◽  
pp. 1369-1374 ◽  
Author(s):  
P. M. Rao ◽  
J. A. Copeck ◽  
A. R. Knight
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Apparent Activation Energy ◽  
Pressure Range ◽  
Excess Energy ◽  
Inert Gases ◽  
Effect Of Temperature ◽  
Primary Process ◽  
Direct Production ◽  
Thiyl Radicals

The photolysis of methyl disulfide vapor in the pressure range 2–25 Torr at wavelengths between 2 300 and 2 800 and at 2 288 Å has been examined and the effect of temperature, pressure, added inert gases, ethyl disulfide, and nitric oxide determined.The primary process is a direct production of two CH3S radicals which have excess energy and which can be observed as methyl thionitrite when NO is present during the decomposition. When pure disulfide is photolyzed the major observable product is methanethiol, although this material accounts for only a small fraction of the primarily produced thiyl radicals whose principal fate is recombination in a substrate-reforming reaction producing excited disulfide molecules. The latter species are deactivated by added gases, or by the substrate itself. The mode of mercaptan formation is by abstraction of H atoms from the substrate by excited CH3S radicals with an apparent activation energy of 1.5 kcal.

Study on the inhibition effect of citric acid on coal spontaneous combustion

Fuel ◽  
2022 ◽  
Vol 310 ◽  
pp. 122268
Author(s):  
Peiyu Liu ◽  
Zenghua Li ◽  
Xiaoyan Zhang ◽  
Jinhu Li ◽  
Guodong Miao ◽  
...  
Keyword(s):  
Citric Acid ◽  
Spontaneous Combustion ◽  
Coal Spontaneous Combustion ◽  
Inhibition Effect

Thermokinetic characteristics of coal spontaneous combustion of Jurassic coal from China

2020 ◽  
Author(s):  
Jingyu Zhao ◽  
Jun Deng ◽  
Furu Kang ◽  
JiaJia Song
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Heating Rate ◽  
Temperature Change ◽  
Thermal Energy ◽  
Spontaneous Combustion ◽  
Heating Rates ◽  
Characteristic Temperatures ◽  
Two Samples ◽  
Jurassic Coal

<p>Jurassic coal samples from two coal mines were selected for oxidative thermal energy experiments. By using a temperature-programmed experimental system, the variation of gaseous products was obtained, and the changes in thermal energy release with temperature were measured. Thermokinetic parameters, such as apparent activation energy (E<sub>a</sub>) and pre-exponential factor (A), of the coal samples under four different heating rates, were determined by thermogravimetric analyzer. The results showed that during the low-temperature oxidation stage, the index gas (CO) used to characterize the spontaneous combustion state of the coal body was roughly the same as the temperature curve of the two samples with the temperature change, but the critical temperature was different. The WD sample produced less CO gas. However, the maximum and minimum exothermic strengths of the two samples showed similar to temperature change curves. The characteristic temperatures for coal were discovered using different heating rates. For the WD sample, the characteristic temperature varied according to the heating rate. For the same type of sample, the TG and DTG curves lagged with an increase in heating rate. Characteristic temperatures T1−T5 had an increasing tendency with an increase in heating rate. As one of the integral methods, Coats-Redfern integral method was adopted to capture the thermokinetic parameters of the samples. The straight line fitting by this method was higher. The heating rate conditions increased from 2 to 15 °C min<sup>-</sup><sup>1</sup> when the oxygen concentration was 21 vol%, the apparent activation energy of the samples decreased with an increase in the heating rate.</p>

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