Modeling and simulation of coal spontaneous combustion in a gob of shallow buried coal seams

Distribution Law of Three Spontaneous Combustion Zones in the Goaf Area of a Fully Mechanized Working Face under High Ground Temperature

“…Therefore, the division of the three spontaneous combustion zones in the goaf area is based on three criteria: air leakage speed, temperature distribution, and O2 concentration [22,23]. Among the three, the air leakage speed is a vector, which is difficult to measure; temperature is the most direct indicator reflecting the degree of spontaneous combustion of the coal, but since the coal is a poor conductor and the heat transfer process in the goaf is very complicated, the temperature changes in each zone of the goaf can hardly be measured; O2 concentration is not only related to the air leakage state, but also related to the degree of oxidation of the leftover coal, in areas of higher degree of spontaneous combustion, the O2 consumption is higher and the O2 concentration is lower, the O2 content directly reflects the oxidation and heat accumulation conditions of the leftover coal [24,25]. Therefore, the scope of the three spontaneous combustion zones can be determined according to the distribution of O2 concentration in the goaf; moreover, O2 concentration is a scalar quantity, which is easy to measure on the site.…”

Targeted inertization with flue gas injection in fully mechanized caving gob for residual coal spontaneous combustion prevention with CFD modeling

“…20,38,39 The development and prevention of spontaneous combustion in gobs also involve multifield coupling problems that include underground fissure fields, flow fields, oxygen concentration fields, and temperature fields. [40][41][42][43][44][45] In this research, the 3D coupling model of coal spontaneous combustion in a fully mechanized caving face was established based on the following basic assumptions: (a) Each component of the mixture gas in the gob was treated as an ideal gas and its flow diffusion was approximated as a stable process. (b) The residual coal and the rock mass in the gob were regarded as continuous and isotropic porous media.…”

“…The spontaneous combustion of coal originates from a series of complex physical and chemical reactions after the coal is exposed to air 20,38,39 . The development and prevention of spontaneous combustion in gobs also involve multifield coupling problems that include underground fissure fields, flow fields, oxygen concentration fields, and temperature fields 40‐45 …”

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

“…As one of the main disasters, coal spontaneous combustion (CSC) not only burns vast coal resources and releases toxic gases but also causes casualties [12][13][14]. In China, 56% of state-owned coal mines have suffered from CSC, accounting for 90-94% of all mine fires [15]. Because coal is a complex organic substance, it will adsorb O 2 to undergo a chain reaction and then release heat when exposed to an O 2 environment.…”

“…However, coal spontaneous fires mostly occur in underground concealed spaces. According to statistics, 60% of CSC occurs in the goaf area [15,20]. Due to large space in the goaf area and wide distribution of residual coal, the dangerous areas of CSC present a three-dimensional distribution.…”