scholarly journals Study on the Effect of Extraneous Moisture on the Spontaneous Combustion of Coal and Its Mechanism of Action

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1969 ◽  
Author(s):  
Yuguo Wu ◽  
Yulong Zhang ◽  
Jie Wang ◽  
Xiaoyu Zhang ◽  
Junfeng Wang ◽  
...  
Keyword(s):  
Technological Process ◽  
Optimization Design ◽  
Spontaneous Combustion ◽  
Combustion Process ◽  
Mining Industry ◽  
Delayed Effect ◽  
Coal Spontaneous Combustion ◽  
Temperature Programmed Oxidation ◽  
Oxidation Stage ◽  
Spontaneous Combustion Of Coal

It is imperative to have an in-depth understanding of the effect of extraneous moisture on the spontaneous combustion of coal not only for the control and prevention of coal spontaneous combustion in the coal mining industry, but also for the optimization design and application of the technological process. In this study, the type of moisture in a coal body has been redefined for the first time from the perspective of disaster prevention and control, i.e., original occurrence of moisture in the coal matrix and the extraneous moisture from the technological process. A suit of coal bodies with different extraneous moisture was prepared by soaking long-flame coal with a low water content. Using a temperature-programmed oxidation test, the effects of extraneous moisture on the temperature increase rate of coal bodies and the emission characteristics of gaseous products during coal spontaneous combustion were studied. Moreover, combined with the characterization of thermal analysis and of pore structure test, the action the mechanism of extraneous moisture on the coal spontaneous combustion process was also explored. The experimental results indicated that the effect of the extraneous moisture content varied with the development of coal spontaneous combustion. In the slow oxidation stage, extraneous moisture played a physical inhibition role in the coal oxidation. In the accelerated oxidation stage, extraneous moisture exhibited a catalytic effect on the coal–oxygen reaction or directly participated in the reaction. After entering the rapid oxidation stage, a delayed effect appeared. When the coal temperature exceeded 180 °C, the spontaneous combustion characteristics of coals with different initial moisture contents gradually tended to achieved balance.

The Comprehensive Fire-Fighting Technology Research of the Section Retracement in Fully Mechanized Workface

2013 ◽  
Vol 709 ◽  
pp. 305-308
Author(s):  
Qun Niu ◽  
Lin Chao Dai ◽  
Fu Dao Liu ◽  
Yu Qiang Guo
Keyword(s):  
Spontaneous Combustion ◽  
Slip Casting ◽  
Mining Industry ◽  
Comprehensive Treatment ◽  
Technology Research ◽  
Coal Spontaneous Combustion ◽  
Nitrogen Injection ◽  
Safe Production ◽  
Spontaneous Combustion Of Coal ◽  
Forecast Technique

Spontaneous combustion of coal is one of the most serious coal mine disasters, which threat the workers' life safety. The paper introduce the comprehensive measures, such as monitor, positive draft technology, nitrogen injection, slip casting, fire preventing and extinguishing under seal, and other relevant coal spontaneous combustion forecast technique used in 1901s fully mechanized workface of FuCheng mining industry, when it has not been mined or its work face has not been removed, which realize the comprehensive treatment of coal spontaneous combustion, guarantee the safe production, and serves as a certain guidance and reference to the efficiency mining of spontaneous combustion coal seam.

scholarly journals Study on the Microscopic Mechanism of Spontaneous Combustion and Oxidation Kinetics of Water-Leached Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Naifu Cao ◽  
Gang Wang ◽  
Yuntao Liang
Keyword(s):  
Kinetic Model ◽  
Moisture Content ◽  
Spontaneous Combustion ◽  
Water Immersion ◽  
Combustion Process ◽  
Oxidation Kinetic ◽  
Oxidation Mechanism ◽  
Temperature Oxidation ◽  
Before And After ◽  
Spontaneous Combustion Of Coal

In this article, a series of experiments have been carried out to study the spontaneous combustion and oxidation mechanism of coal after water immersion and investigate its tendency to spontaneous combustion, analyze the difficulty of spontaneous combustion of coal samples under different water immersion conditions, and establish a kinetic model of water immersion coal oxidation (taking the Bulianta 12# coal as a case study). They rely on physical oxidation adsorption, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetry, and oil bath heating. SEM has been used to analyze the characteristics of coal pore structure under different water immersion conditions (water-saturated coal samples under different water loss conditions until the coal samples are completely dried); FTIR served to investigate the characteristics of the molecular chemical structure of the coal surface before and after the coal is immersed in water. Through programmed temperature oxidation experiments combined with FTIR analyses and gas chromatographic (GC) analysis of gaseous products, it has been possible to study the changes of molecular structure and gas products on the surface of coal samples at different temperatures and water immersion conditions. The oxidation reaction rate of the 12# coal samples of Shendong Mine’s Bulianta Mine under different water content conditions during the spontaneous combustion process has been quantitatively studied. The difficulty of spontaneous combustion of coal samples has been correspondingly addressed. A kinetic model from the perspective of oxygen consumption has been proposed. Thermogravimetry-differential scanning calorimetry (TG-DSC) has been used to analyze and study the exothermal oxidation process before and after coal immersion. From the perspective of the exothermic intensity of the coal-oxygen reaction, an oxidation kinetic model for immersed coal samples has been developed to qualitatively determine its spontaneous combustion tendency. Results have shown that the increase in the specific surface area increases the risk of spontaneous combustion, and coal samples after soaking and drying have a stronger tendency to spontaneous combustion than raw coal. The moisture content of the coal sample leading to the easiest ignition conditions is 16.05%. Regardless of the moisture content, the critical temperature is maintained at 65–75°C, and the temperature of the left coal in the goaf should be prevented from exceeding this critical value.

scholarly journals Effects of organic sulfur on oxidation spontaneous combustion characteristics of coking coal

2021 ◽  
pp. 014459872110490
Author(s):  
Fei Gao ◽  
Zhe Jia ◽  
Mei-ling Qin ◽  
Xiao-gang Mu ◽  
Yi-fei Teng ◽  
...  
Keyword(s):  
Sulfur Content ◽  
Photoelectron Spectroscopy ◽  
Spontaneous Combustion ◽  
Characteristic Temperature ◽  
Combustion Process ◽  
Oxidation Products ◽  
Organic Sulfur ◽  
Scanning Calorimetry ◽  
Clean Coal ◽  
Spontaneous Combustion Of Coal

Research on the spontaneous combustion of coal caused by sulfur has always been focused on pyrite in coal but has rarely considered the influence of organic sulfur. In this paper, coal samples, rather than model compounds, were used to study the influence of organic sulfur content in coal on its spontaneous combustion process. The results of X-ray photoelectron spectroscopy and thermogravimetry, differential scanning calorimetry, and mass spectrometry indicate that organic sulfur in Shuiyu clean coal exists in forms of mercaptan, thioether, sulfone (sulfoxide), and thiophene. With the decrease of organic sulfur content, the characteristic temperature points and the peak values of the exothermic curves in the process of coal oxidation spontaneous combustion all shifted toward higher temperatures. The ignition activation energy of coal also increased, and the initial and peak gas evolution temperatures of the oxidation products shifted toward higher temperatures. These findings suggest that the reduction of organic sulfur content can inhibit the oxidation process and spontaneous combustion tendency of coal. This effectively reveals the mechanism of the spontaneous combustion of coal and is of great significance to future studies in this field.

scholarly journals Influence of Air Supply on Coal Spontaneous Combustion During Support Withdrawal in Fully Mechanized Coal Mining and its Prevention

2021 ◽  
Author(s):  
Xiaowen Zhang ◽  
Xihua Zhou ◽  
Gang Bai ◽  
Cheng Wang
Keyword(s):  
Spontaneous Combustion ◽  
Characteristic Temperature ◽  
Effect Of Temperature ◽  
Withdrawal Period ◽  
Coal Spontaneous Combustion ◽  
Hydrocarbon Gases ◽  
Working Face ◽  
Air Supply ◽  
Spontaneous Combustion Of Coal ◽  
Temperature Programmed

Abstract It is important to study the oxidation characteristics of coal samples under different air supply rates to prevent spontaneous combustion of coal, particularly when the air supply rate at the working face needs to be changed during support withdrawal. In this work a self-designed temperature-programmed experimental device was used to study the change laws of various index gases released during the spontaneous combustion of coal under various air supply conditions. The study focused on the analysis of the low-temperature (30–200 ℃) oxidation stage, the increase in air supply, and the concentration change process of four hydrocarbon gases (C2H6, C3H8, C2H4, and C2H2) generated by the coal sample. The change law of the CO generation rate under the combined effect of temperature and air supply was analyzed, and surface fitting was performed to determine the characteristics of phased changes. Based on the working face parameters of the Yangchangwan Coal Mine, this study predicted the CO concentration at the upper corner of the working face at the characteristic temperature of coal spontaneous combustion during the withdrawal period. The paper summarizes comprehensive safety measures that can help prevent spontaneous combustion during the withdrawal period.

scholarly journals Overview of Research and use of Indicator Gases of Coal Spontaneous Combustion in China / Přehled Výzkumu a Využití Indikačních Plynů Samovznícení Uhlí V Číně

2014 ◽  
Vol 60 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Xiyang Feng ◽  
Alois Adamus
Keyword(s):  
Spontaneous Combustion ◽  
Experimental Methods ◽  
Paper Briefly ◽  
Coal Spontaneous Combustion ◽  
Laboratory Equipment ◽  
Significant Development ◽  
The Sixties ◽  
Mine Fires ◽  
Spontaneous Combustion Of Coal ◽  
Program Characteristics

Abstract The beginnings of research and use of results in the area of indicator gas application for early detection of spontaneous combustion of coal in China comes from the sixties of the last century. The significant development occurred in the nineties, when the program “Characteristics of the adsorption of coal oxygen and its application in the prevention of mine fires” had been completed. The paper briefly describes an overview of the historical development, achievements, experimental methods, laboratory equipment, legislation, and the outlook for the use of indicator gases of coal spontaneous combustion in China

scholarly journals Experimental study on the spatial and temporal variations of temperature and indicator gases during coal spontaneous combustion

2020 ◽  
pp. 014459872096416
Author(s):  
Junchao Chen ◽  
Lin Li ◽  
Deyi Jiang ◽  
Lei Zhou ◽  
Liang Wang
Keyword(s):  
Oxygen Consumption ◽  
Spontaneous Combustion ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Coal Spontaneous Combustion ◽  
Accelerated Oxidation ◽  
Air Supply ◽  
Oxidation Stage ◽  
Higher Temperature ◽  
Temperature Area

Coal spontaneous combustion is one of the main potential hazards in the process of mining. To study the spatial and temporal variations of higher-temperature area and indicator gases, an adiabatic oxidation testing system was developed to simulate the whole process of coal spontaneous combustion. The experimental results show that the entire process of coal spontaneous combustion could be divided into three stages: slow-oxidation, accelerated-oxidation and combustion stages. In the slow-oxidation stage, the higher-temperature area shifted slowly from the bottom to the top and then stayed at the top until accelerated-oxidation stage was reached; [Formula: see text] and [Formula: see text] concentration remained more or less constant as well as the oxygen concentration. In accelerated-oxidation stage, the higher-temperature area moved to the bottom rapidly and subsequently stayed approximately in the center of the coal; [Formula: see text], [Formula: see text] concentration and oxygen consumption increased sharply. In addition, the occurrence of higher-temperature area is accompanied by higher oxygen consumption. The obtained results show that higher air supply rate could shorten spontaneous combustion period and there exists a hyperbolic relationship between the temperature and time.

Numerical Simulation and Backfilling Materials Research on Coal Spontaneous Combustion of Thick Seam Large-Scale Top-Caving Region in Resources Conformity Coal Mine

2012 ◽  
Vol 524-527 ◽  
pp. 317-320
Author(s):  
Bo Tan ◽  
Yuan Gang Jiang ◽  
Chao Nan He ◽  
Jing Chang ◽  
Ya Qi Luo
Keyword(s):  
Numerical Simulation ◽  
Process Model ◽  
Large Scale ◽  
Spontaneous Combustion ◽  
Combustion Process ◽  
Fire Control ◽  
Coal Spontaneous Combustion ◽  
Thick Seam ◽  
Materials Research ◽  
And Control

This paper aimed at fire control in thick seam large-scale top-carving region. On the basis of coal and oxygen compounding theory, theoretical analysis, numerical simulation and experiment are combined, and a coal spontaneous combustion process model is built according to fluid mechanics and control theory. By studying and testing on top-carving coal spontaneous combustion process, conclusion is drawn that spontaneous combustion area is the largest in partly-closed region, followed by unclosed region. A totally closed baffle leads to the smallest spontaneous combustion area and the smallest possibility of fire. With local materials in a certain condition, new, cheap backfilling materials are developed. Thus provide theoretical basis for study on the forecasting and prevention of thick seam large-scale top-carving coal spontaneous combustion.

scholarly journals Experimental study on thermal effect and gas release laws of coal-polyurethane cooperative spontaneous combustion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haiyan Wang ◽  
Yao Tian ◽  
Jinglei Li ◽  
Xiao Chen
Keyword(s):  
Binary System ◽  
Mass Fraction ◽  
Spontaneous Combustion ◽  
Combustion Process ◽  
Great Influence ◽  
Oxygen Absorption ◽  
Gas Release ◽  
Initial Release ◽  
Combustion Simulation ◽  
Spontaneous Combustion Of Coal

AbstractThis paper presents a research on the kinetics and gas release laws of the cooperative spontaneous combustion of coal-polyurethane binary system by means of thermogravimetric analysis and spontaneous combustion simulation experiments. The coal-polyurethane binary system is more prone than individual samples to combustion. The polyurethane mass fraction has a great influence on the cooperative spontaneous combustion process. As the polyurethane mass fraction rises, the activation energies of oxygen absorption stage and pyrolysis stage decrease. The combustion residues of coal-polyurethane binary system scorches into lumps and the surfaces of the particles become rougher. During spontaneous combustion, the initial release temperatures of the four gases CO2, CO, C2H6 and C2H4 drop as the polyurethane mass fraction increases. The gas release amount of them increases with increasing polyurethane mass fraction. And the amount of CH4 decreases as the polyurethane mass fraction increases. The CO/CO2 ratio with temperature for different polyurethane mass fraction have the same trends. The results of this study have implications concerning polyurethane materials application and fire protection in coal mine.

scholarly journals A Study on Preventing Spontaneous Combustion of Residual Coal in a Coal Mine Goaf

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Yongjun Wang ◽  
Xiaoming Zhang ◽  
Yuichi Sugai ◽  
Kyuro Sasaki
Keyword(s):  
Spontaneous Combustion ◽  
Mine Ventilation ◽  
Ventilation Network ◽  
Leakage Flow ◽  
Coal Spontaneous Combustion ◽  
Economical Method ◽  
Long Period ◽  
Simulation Results ◽  
Spontaneous Combustion Of Coal ◽  
Residual Coal

The effectiveness of grouting scheme has been simulated to prevent the coal spontaneous combustion at a goaf in Haizi Colliery, China. The colliery has been operated for long period over 27 years and has a complex ventilation network including airflow leakages which could possibly lead to the spontaneous combustion of coal at goafs. Firstly, the mine ventilation simulator MIVENA was used to analyze the mine ventilation network airflows to control airflows in and out of working faces and goafs. As the second approach, numerical simulations were carried by the simulator FLUENT in order to predict spontaneous combustion of residual coal with leakage flow in the #3205 goaf. It was cleared that the goaf can be divided into three zones based on oxygen concentration in the goaf area. Finally, the numerical simulation results show that the slurry grouting method is able to be an effective and economical method by reducing porosity in the goaf area to prevent spontaneous combustion of residual coal.

scholarly journals Detection and location of places of spontaneous combustion of coal in mines due to gas anomalies on the earth’s surface

2020 ◽  
Vol 174 ◽  
pp. 01061
Author(s):  
Vyacheslav Portola ◽  
Alyona Bobrovnikova ◽  
Georgii Shirokolobov ◽  
Dmitiy Paleev
Keyword(s):  
Molecular Diffusion ◽  
Spontaneous Combustion ◽  
Control Method ◽  
Air Pressure ◽  
Coal Spontaneous Combustion ◽  
The Earth ◽  
Underground Fire ◽  
Spontaneous Combustion Of Coal

The effectiveness of localization and extinguishing of places of underground fires that occur in mine worked out spaces depends on information about the location of a place of spontaneous combustion. Existing methods to detect the processes of coal spontaneous combustion in mines include monitoring the content of gases in mine atmosphere, released during the spontaneous combustion of coal. However, this control method does not allow determining the location of a place of combustion, since the paths of gas movement in the worked out space are unknown. The surface gas survey allows to determine the location of the underground fire. The calculations showed that gases, generated in the fire seat, spread to the earth’s surface due to molecular diffusion, the thermal depression developed by the fire seat and the drops of air pressure created by the ventilation fans. The dependences of the distribution of fire gases content in rocks on the rate of drops of air pressure between the worked out space in a mine with a fire seat and the atmosphere on the surface of the earth are obtained. Mine researches have confirmed the formation of anomalies of fire gases in rocks and soil over places of spontaneous combustion of coal occurred in worked out space. When conducting a gas survey, it is sufficient to measure the content of fire gases in the soil at a depth of 0.5-1.0 m.

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