[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

An experimental study for characterization the process of coal oxidation and spontaneous combustion by electromagnetic radiation technique

Three-dimensional modeling and analysis of macro-pore structure of coal using combined X-ray CT imaging and fractal theory

Gas desorption characteristics effected by the pulsating hydraulic fracturing in coal

Experimental analysis of the pore structure and fractal characteristics of different metamorphic coal based on mercury intrusion-nitrogen adsorption porosimetry

In recent years, the ecology, security, and sustainable development of modern mines have become the theme of coal mine development worldwide. However, spontaneous combustion of coal under conditions of oxygen supply and automatic exothermic heating during coal mining lead to coalfield fires. Coal spontaneous combustion (CSC) causes huge economic losses and casualties, with the toxic and harmful gases produced during coal combustion not only polluting the working environment, but also causing great damage to the ecological environment. China is the world's largest coal producer and consumer; however, coal production in Chinese mines is seriously threatened by the CSC risk. Because deep underground mining methods are commonly adopted in Chinese coal mines, coupling disasters are frequent in these mines with the coalfield fires becoming increasingly serious. Therefore, in this study, we analyzed the development mechanism of CSC. The CSC risk assessment was performed from the aspects of prediction, detection, and determination of the "dangerous area" in a coal mine (i.e., the area most susceptible to fire hazards). A new geophysical method for CSC determination is proposed and analyzed. Furthermore, the main methods for CSC fire prevention and control and their advantages and disadvantages are analyzed. To eventually construct CSC prevention and control integration system, future developmental direction of CSC was given from five aspects. Our results can present a reference for the development of CSC fire prevention and control technology and promote the protection of ecological environment in China.

A review on the mechanism, risk evaluation, and prevention of coal spontaneous combustion in China

Coal seam water infusion is a universal comprehensive mine disaster prevention method practiced worldwide. The result of water infusion is determined by the structure and seepage characteristics of the coal sample around the borehole. In this paper, the structure and seepage characteristics of the coal sample under various stress and pore water pressures are measured via nuclear magnetic resonance (NMR) technology; the influence rule of confining pressure and pore water pressure during the test on the coal sample structure and seepage characteristics is analyzed. Based on fractal geometrical theory, the fractal model of permeability is created. The results show that the coal sample with water infusion has an intertwined internal fracture-pore structure and that the pore radius distribution is diverse. Through theoretical analysis and discussion, we found that there are no large changes in the pore area fractal dimension and the measured pore volume fractal dimension, but the trends of changes in these two fractal dimensions are opposite, because the pore area fractal dimension characterizes the homogeneity of the pore area distribution on the surface of a coal sample, and the measured pore volume fractal dimension characterizes the cumulative volumetric changes in the pores inside a coal sample. The changes in these two fractal dimensions validate that the pore structures inside a coal sample have similar in fractal characteristics and demonstrate that the coal seam water infusion technique will not damage the skeleton of the coal sample. The variation rules of theoretical permeability from the fractal model and the value from the liquid measurement versus confining pressure and pore water pressure are consistent, an increase in the water pressure will result in an increase in the permeability, and an increase in the confining pressure will result in a decrease in the permeability. However, because the seepage channels with a large diameter in the tested coal sample were blocked, there is a relatively large difference between the two permeabilities. Therefore, increasing the connectivity between the seepage channels with a large diameter will improve the effects of water infusion, which is implemented to prevent disasters. Through NMR experiment and theoretical analysis, this study establishes a quantitative relationship between the pore structures inside the coal sample and its permeability during coal seam water infusion process, provides an advanced experimental approach and theoretical analysis method, which will be of great importance in the improvement in the water infusion process implemented in deep working coal seams to prevent disasters and in the determination of the range of application of this process and the evaluation metrics for this process.

Experimental Study on the Pore Structure Fractals and Seepage Characteristics of a Coal Sample Around a Borehole in Coal Seam Water Infusion

Non-linear seepage characteristics and influential factors of water injection in gassy seams

A comprehensive method for studying pore structure and seepage characteristics of coal mass based on 3D CT reconstruction and NMR

Study on the seepage characteristics of coal based on the Kozeny-Carman equation and nuclear magnetic resonance experiment

Zhen Liu

Papers

A review on the mechanism, risk evaluation, and prevention of coal spontaneous combustion in China

Experimental Study on the Pore Structure Fractals and Seepage Characteristics of a Coal Sample Around a Borehole in Coal Seam Water Infusion

Non-linear seepage characteristics and influential factors of water injection in gassy seams

A comprehensive method for studying pore structure and seepage characteristics of coal mass based on 3D CT reconstruction and NMR

Study on the seepage characteristics of coal based on the Kozeny-Carman equation and nuclear magnetic resonance experiment