Characteristics of HPMC/PEG/CS Thermosensitive Hydrogel Inhibiting Coal Spontaneous Combustion: An Experimental Study

ABSTRACT

Coal spontaneous combustion disasters frequently appear in the process of coal mining, which brings great-hidden danger to mine safety production. To effectively inhibit coal spontaneous combustion, HPMC/PEG/CS thermosensitive hydrogels with quick phase-transition response times and excellent thermal stability have been developed in this study. Then, the effects of HPMC/PEG/CS thermosensitive hydrogel on microscopic groups of coal molecules at the corresponding temperature and coal spontaneous combustion heating processes are analyzed by using Fourier transform infrared spectrometry, temperature-programmed and thermogravimetric experiments. The results reveal that the gel skeleton shows porous structure and connects with each other, which improves the thermal stability and endothermic cooling capacity of the system. Compared with raw coal, the oxygen-containing groups and aliphatic hydrocarbon active groups of HPMC/PEG/CS thermosensitive hydrogel treated coal are decreased. In addition, the characteristic temperature point of CO rapid release is postponed, and its inhibition rate is 74.48%. Simultaneously, the apparent activation energy of different oxidation stages is increased. The characteristic temperature point of coal spontaneous combustion oxidation process is delayed, thus improving the difficulty of coal spontaneous combustion reaction. HPMC/PEG/CS thermosensitive hydrogels can inhibit coal spontaneous combustion reactions by reducing the activity of coal molecules and delaying the process of coal spontaneous combustion reactions through releasing water, absorbing heat, cooling, and covering oxygen.

KEYWORDS:

• Thermosensitive hydrogel
• coal spontaneous combustion
• coal molecule microstructure
• apparent activation energy
• characteristic temperature

Acknowledgements

This study is supported by the National Natural Science Foundation of China (No. 52174206); Shaanxi Provincial Department of education Youth Innovation Team scientific research plan project (No. 21JP047); China Postdoctoral Science Foundation-regional special support program (No. 2022MD713797).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the National Natural Science Foundation of China [52174206]; Shaanxi Provincial Department of education Youth Innovation Team scientific research plan project [21JP047]; China Postdoctoral Science Foundation-regional special support program [2022MD713797]