Experimental study on the effects of pre-oxidation on the pore structure and fractal characteristics of coal

ABSTRACT

To assess the effects of pre-oxidation on pore structures and fractal features of coal samples, pre-oxidized coals at various oxidation temperatures were prepared and compared. Pore structure parameters of coal samples were analyzed qualitatively and quantitatively using electron scanning microscopy (SEM) and N₂ adsorption. The pore volume of coal samples increased first and then decreased with the increase of oxidation temperature. Among them, the pre-oxidized coal at 150°C is the highest, which is 27.92% higher than the raw coal. The fractal features of coal samples were calculated by fractal theory. It was found that pre-oxidation makes pore fissures of coal samples develop with obvious pore expansion effect, which is more obvious at the higher pre-oxidation temperature. In addition, fractal dimension D₂ of coal samples was increased by pre-oxidation, indicating that pore structures of pre-oxidized coal are more complex than those of raw coal.

KEYWORDS:

• Pre-oxidation
• N₂ adsorption
• intrinsic components
• pore fissure
• fractal characteristics

Disclosure statement

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

Author contribution

Hongqing Zhu: Formal analysis and writing-original draft. Houwang Wang: Formal analysis and supervision. Linhao Xie: Software, Validation. Wenzhou Du: supervision, validation.

Additional information

Funding

This work was work was provided by the National Natural Science Foundation of China [No.51774290].

Notes on contributors

Hongqing Zhu

Hongqing Zhu is a professor at China University of Mining and Technology (Beijing). He has been engaged in scientific research and teaching in the field of safety for a long time.

Houwang Wang

Houwang Wang is a doctoral degree in safety science and engineering at China University of Mining and Technology (Beijing). He is engaged in coal mine fire prevention and prediction.

Linhao Xie

Linhao Xie is a doctoral degree in safety science and engineering at China University of Mining and Technology (Beijing). He is engaged in the application of new chemical inhibitors for fire prevention and extinguishing.

Wenzhou Du

Wenzhou Du is an associate professor at Shandong University of Science and Technology, China. He is engaged in scientific research and teaching in the fields of fire and explosion prevention theory and technology, mine ventilation and system optimization, and emergency technology and management.