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Kinetics of self-heating and spontaneous combustion of coal dumps
L.I Stefanovich1*,
E.P. Feldman1
1Branch for
Physics of Mining Processes of the M.S. Poliakov
Institute of
Geotechnical
Mechanics of the National Academy of Sciences of Ukraine, Dnipro, Ukraine
*Corresponding
author: e-mail: listef2591@gmail.com
Physical and technical
problems of mining production, 2023, (25), 31-41.
https://doi.org/10.37101/ftpgv25.01.003
full text (pdf)
ABSTRACT
Purpose. Studying the kinetics of
self-heating and spontaneous combustion of coal dumps under conditions of
free access of oxygen inside the dump, as well as elucidating the influence
of the process of burning out the coal component of the dump on its
temperature regime.
Methods. The work uses methods of
physical and chemical kinetics, as well as methods of numerical solution of
the system of evolutionary equations.
Findings. A mathematical model of the
self-heating of a coal shaft was built, which
makes it possible to obtain the dependence of the dump average temperature
on time. The multi-stage thermal regime of the dump was
revealed. The temperature threshold for the occurrence of the
self-ignition stage of the dump is theoretically
estimated, which correlates with known experimental results.
Originality. The
physical and mathematical model of the process constructed in the work
shows that, regardless of the initial content of the coal component (in the
range of values from 5% to 7%), the process of evolution of the average
temperature of the dump can be divided into 3 different stages, namely: the
first stage is associated with slow self-heating the dump to a certain
critical temperature, the second stage occurs after the critical
temperature is exceeded and is of a sharp (explosive) nature, corresponding
to the spontaneous self-combustion of the dump. And
finally, after the coal component of the dump burns out, the third
stage of extremely slow cooling of the dump begins, which can last for
years.
Practical implications. The results obtained in the
work can be useful for assessing the temperature conditions of coal dumps,
depending on the initial content of the coal component. They can be used to predict the fire hazard of mine dumps.
Keywords: coal dump, self-heating, self-combustion, burnout of the dump coal component
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