Evolution mechanism of microstructure and oxidation reactivity of pre-oxidized coal under thermal-tensile stress coupling
Year: 2026
Type: article
Abstract: Deep-mine residual coal often undergoes pre-oxidation, thermal disturbance, and tensile damage, altering its pore structure, oxygen transport, and oxidation reactivity. To elucidate the evolution mechanism under thermal-tensile stress coupling, pre-oxidized coking coal samples were studied using thermal analysis, pore characterization, oxygen transport simulation, FTIR, and ESR. Results show that the coupled effect reconstructs the pore-fracture network, enlarging oxygen pathways. As pore size increases from 0.5 to 5 nm, the O 2 diffusion coefficient rises from 3.97 to 9.85 Å 2 /ps, indicating enhanced oxygen transport. The thermal-tensile coupling exerts stage-dependent regulation: the maximum endothermic temperature (TD1) is delayed by 8.97–14.91 °C, enhancing low-temperature physical endothermy; the initial exothermic temperature (TD2) drops by 2.89–9.95 °C; the ignition temperature (TD3) shifts lower; total heat release increases by 9.88–17.15%, intensifying medium-to-high temperature oxidation FTIR and ESR reveal that aliphatic side-chain cleavage, carbonyl/carboxyl formation, and free-radical accumulation promote radical-chain oxidation upon reheating. CRITIC analysis indicates that dominant risk factors shift sequentially from oxygen-containing functional group activation and initial radical generation (before TD1) to aliphatic decomposition, radical accumulation, and enhanced heat release (after TD2). This study reveals a stage-dependent transition from low-temperature inhibition to medium-/high-temperature oxidation promotion in pre-oxidized coal under thermal-tensile stress coupling, offering theoretical support for controlling thermal instability in disturbed deep-mine residual coal.
Authors: Cong Ding, Ji Wu, Zongxiang Li, Lin Li, Gang Bai, Bing Lu
Institutions: Liaoning Technical University, Henan Polytechnic University
Language: English
Subfield: Fuel Technology
Field: Energy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,620
Award: G8862262686
OpenAlex ID: W7208739253