Multi-method analysis of the nonlinear influence of moisture content on the surface structure and oxidation characteristics of bituminous coal

• DOI: 10.25259/ajc_5_2024
• Publication Date: 2025-03-11T10:41:48Z
• Authors: Yu Liu; Yan Chen; Dongjie Hu; Zongxiang Li; Chunhua Zhang; Xiaodong Zhang

To investigate the nonlinear influence mechanism of moisture content on the self-ignition propensity of bituminous coal, multiple advanced analytical techniques, including scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), synchronous thermal analysis, gas adsorption, closed-coal oxidation, and ReaxFF molecular dynamics simulations, were employed to conduct a multi-method analysis of coal samples with varying moisture contents. Surface morphology, elemental distribution, thermal characteristics, oxidation reactivity, and pyrolysis products were examined at the micro and molecular levels. Results revealed that under identical experimental conditions, compared to raw coal (1.3% moisture content) and other samples with moisture content above 5%, the coal sample with 5% moisture content exhibited higher surface roughness, more developed pore structure, and higher oxygen content. This sample also demonstrated the lowest ignition apparent activation energy (88.80 KJ·mol-1), highest oxygen adsorption capacity, and fastest oxygen consumption rate. ReaxFF force field simulations of Wiser coal molecule pyrolysis indicated that moisture content between 5% and 10% favored the generation of self-ignition indicator gases such as acetylene and ethylene. The self-ignition propensity of coal samples with moisture content above 5% weakened as moisture content increased. This research has revealed a nonlinear relationship between moisture content and the oxidation characteristics of coal, providing a theoretical foundation and technical guidance for optimizing coal storage and transportation conditions, enhancing coal utilization efficiency, and improving safety measures.