Inhibition of coal spontaneous combustion by an environment-friendly, water-based fire extinguishing agent

• Published in: Journal of thermal analysis and calorimetry 2021-04, Vol.144 (2), p.325-334
• Main Authors: Zhai, Xiao-Wei, Pan, Wen-Jun, Xiao, Yang, Wang, Shi-rong, Ouyang, Li-ming
• Format: Article
• Language: English
• Subjects: Absorption; Activation energy; Analytical Chemistry; Chemistry; Chemistry and Materials Science; Coal; Combustion; Electric properties; Fire prevention; Heat conductivity; Heat transfer; Heat treatment; Heating; Inorganic Chemistry; Measurement Science and Instrumentation; Oxidation; Physical Chemistry; Polymer Sciences; Reaction kinetics; Spontaneous combustion; Surface chemistry; Thermal analysis; Thermal conductivity; Thermal decomposition; Thermal diffusivity; Thermal properties; Thermal stability; Thermodynamic properties; Thermophysical properties
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-020-10101-6

At present, inhibitors have been widely used in the field of coal fire prevention and control, but there are some defects in the use of them. So it is necessary to find a new practical and economical inhibitor. Dissolvable tiny-foam extinguisher (DTE) is environment-friendly, high in thermal stability, and fast in cooling. In view of the good performance of the product, the thermal behavior effects of DTE on coal spontaneous combustion were investigated through experimental tests. A scanning electron microscopy was used to study changes in the surface microstructure of raw coal after DTE treatment. Laser thermal conductivity analysis and simultaneous thermal analysis were used to test the effects of DTE at mass fraction of 0%, 5%, 10%, and 15% on the thermophysical properties, mass loss, characteristic temperature, and heat release of coal during heating. The surface of the DTE-treated coal sample was covered in a dense film. The treated coal sample had lower thermal diffusivity and thermal conductivity values and a higher specific heat capacity. Moreover, coal treated with DTE showed no obvious oxygen absorption or mass gain during initial heating, and the dry cracking temperature was greatly increased by 37 °C, 53 °C, and 100 °C, respectively. The initial heat release temperature increased by more than 170 °C, and the amount of the initial heat absorption was more than 52.2 times that of untreated samples. Oxidation kinetics were applied to calculate the activation energy of the coal during thermal decomposition and ignition, and the activation energies of the treated samples at the thermal decomposition and combustion stages increased by 161%, 179%, and 173%, respectively. From these results, we concluded that DTE could inhibit heat accumulation by blocking oxygen contact with the coal and greatly reducing heat release during heating. Besides, only a small quantity of DTE was needed to effectively inhibit coal self-ignition. These results provide reference for the field application of DTE in restraining coal spontaneous combustion.