Prevention and Control of Coal Spontaneous Combustion by Novel Phenolic Resin–Clay Thermosetting Ultrafine Particle Aerosol

Abstract

In this study, thermally consolidating ultrafine aerosol particles (<100 μm) were prepared using a phenolic resin, kaolin, montmorillonite, and hydrotalcite in a ratio of 68:16:8:8 and subsequently used to control hidden spontaneous fires in underground coal mines. Thermogravimetric/differential scanning calorimetry analysis revealed that the aerosol exerts a significant suppression effect on the exotherm at 360–600 °C, and after treatment, the oxidation kinetic parameters increased by 65.6%. From Fourier transform infrared spectral results, it was found that functional groups in coal (such as −COOH and −OH) varied clearly. Scanning electron microscopy images revealed that aerosol particles from dense insulation layers exhibit a remarkable thermosetting property at temperatures greater than 200 °C. The energy level, charge distribution, and thermodynamic parameters of the composite process were calculated using quantum simulations for the shells generated by curing the optimized PF-minerals at temperatures greater than 200 °C. The maximum contribution of the bidentate ligand to the highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital in the PF-mineral complexes decreased by five atoms, and the maximum energy difference of the frontier orbitals reached 3.586647 eV. The absolute value of the HOMO energy increased by 48.1%, indicating that the complex formed by the phenolic resin is hardly oxidized. An aerosol transport experiment and simulated fire extinguishing experiment confirmed that the aerosols form a stable system in air and that ultrafine particle aerosol materials effectively suppress fires that are caused by the spontaneous combustion of coal.

Exploring the Effect of Low-Temperature Oxidation on the Petrophysical Characteristics of Coal

“…Coal is still the main fossil energy even under the general trend of carbon neutrality. − However, due to the poor thermal conductivity of coal, − it easily causes heat accumulation, which evolves coal spontaneous combustion (CSC), resulting in the waste of resources. − Therefore, it becomes highly necessary to study how the pore fissure characteristics do an impact on CSC from the perspective of structure …”