Study on the Spontaneous Combustion Oxidation Properties of Coal under the Coupling Effect of Stress and Temperature

ABSTRACT

Kilometer-deep mines have become the new norm in coal mining. To study the influence of high stress-high ground temperature coupling conditions in deep mines on the oxidative exothermic characteristics of coal, this paper pre-treats coal samples under different stress and different temperature coupling conditions, and then conducts oxidation temperature tests on coal samples. By analyzing the parameters of initial exothermic temperature, exothermic heat and apparent activation energy of coal, the influence law of stress-temperature coupling on the oxidative exothermic properties of coal was obtained. The results show that when the initial temperature is 313 K, the initial exothermic temperature of coal decreases first and then increases with increasing initial stress. The exothermic heat and activation energy change trends in the initial exothermic stage are the same, both show atrend of first decreasing and then increasing, and both reach their minimum values at 10 MPa. When the initial stress is 5 MPa, the initial exothermic temperature of coal first increases and then decreases with increasing initial temperature. Both the exothermic and apparent activation energy of coal in the initial exothermic stage showed atrend of increasing and then decreasing, and reached the inflection point at the initial temperature of 323 K. The research results provide theoretical support for the prevention and control of spontaneous combustion in deep mines.

KEYWORDS:

• Coal spontaneous combustion
• low temperature oxidation
• stress-temperature coupling
• characteristic temperature
• oxidation kinetics

Acknowledgments

This work was funded by the National Natural Science Foundation of China (Grant No.52004084, 51674103) and the Henan Province Key R&D and Promotion Special (Technology Tackling Key) Project (212102310388). The authors wish to thank these organizations for their support. They also wish to thank their reviewers and editors for their constructive comments and suggestions for improving the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51674103,52004084]; the Henan Province Key R&D and Promotion Special (Technology Tackling Key) Project [212102310388].