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Research on Reaction Mechanism of Different Stages of Lean Coal Spontaneous Combustion Based on Thermogravimetric Analysis: A Case Study of 1307 Working Face

Environment and Resource / 2025,7(1): 112-124 / 2025-09-08 122 70

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• Authors:
• Information:

  1. School of Coal Engineering, Shanxi Datong University, Datong;
  2. Oilfield Technology Engineering Company, CNOOC Energy Technology & Services Company Limited, Tianjin

• Keywords:
  Spontaneous combustion of coal; Chromatographic oxygen absorption; Thermogravimetricdifferential scanning calorimetry; Kinetic mechanism
• Abstract: In response to the urgent need for preventing and controlling the spontaneous combustion of abandoned coal in goaf areas of high-gas mines, this paper focuses on the lean coal located in the 1307 working face of a specific mine as the research subject. Through a combination of on-site sampling, chromatographic oxygen inhalation identification, and thermogravimetric-differential scanning calorimetry experiments, this study systematically reveals the dynamic evolution of the spontaneous combustion process of lean coal. Research indicates that this coal seam exhibits a pronounced tendency for spontaneous combustion, and its oxidation process demonstrates significant phase characteristics. During the increase in temperature gradient, the coal sample undergoes a continuous transformation characterized by initial weight loss due to water evaporation, followed by weight gain attributable to oxidation, and culminating in intense combustion. The mass change trend shifts from an initial decline to a temporary increase, ultimately resulting in a sharp loss. The heat release behavior transitions gradually from heat absorption at lower temperatures to a significant escalation in heat release intensity, with a notable enhancement in heat release capacity during the combustion phase. The evolution of the kinetic mechanism is particularly crucial, as the activation energy increases incrementally with rising temperature. The reaction mechanism transitions from a multi-molecular layer model in the lowtemperature region, through a medium-temperature contraction reaction mode, and ultimately to a hightemperature, two-stage kinetic dominance. This progression reveals the chain reaction nature of coal spontaneous combustion, transitioning from physical adsorption to the breaking of chemical bonds. This research establishes a foundational mechanism for the precise prevention and control of spontaneous combustion in abandoned coal areas within goaf regions.
• DOI: https://doi.org/10.35534/er.0701009
• Cite: Zhao, W. S., Zhou, J. Y., Wang, J. N., Gao, C. (2025). Research on Reaction Mechanism of Different Stages of Lean Coal Spontaneous Combustion Based on Thermogravimetric Analysis: A Case Study of 1307 Working Face. Environment and Resource, 7(1), 112-124.