Inhibition Characteristics of Gel-Based TiO₂/OPC/CPAAM Composite Inhibitor to Control Coal Spontaneous Combustion

ABSTRACT

Spontaneous combustion of coal is a major problem in coal industry. In order to improve the environmental performance and effectiveness of existing inhibitors used to inhibit coal spontaneous combustion, this study utilized physical inhibitors such as chitosan (CS), acrylic acid (AA), and acrylamide (AM) and copolymerized them with the chemical inhibitor procyanidin (OPC). The resulting composite inhibitor was then in situ polymerized with modified nano-TiO₂ to create an environmentally friendly gel-based composite inhibitor, referred to as TiO₂/OPC/CPAAM. Scanning electron microscopy analysis revealed a significant increase in the number of laminar folds and pores within the inhibited coal samples. Additionally, thermogravimetric analysis showed that all characteristic temperature points of the inhibited coal samples were raised, with an average increase of 21.34%. Differential scanning calorimetry also indicated a reduction in the total heat release and heat release intervals of the inhibited coal samples. Gas infrared spectroscopy provided evidence that the inhibitory treatment significantly slowed the growth of CO and CO₂ during the heating process of the coal samples, leading to an improvement in environmental performance. Furthermore, diffuse reflection infrared spectroscopy testing demonstrated that the inhibitory treatment resulted in the passivation of active groups’ free hydroxyls and an increase in the content of stable group ether bonds. Overall, the results of this study indicate that the composite inhibitor TiO₂/OPC/CPAAM offers superior inhibition effects on coal spontaneous combustion.

KEYWORDS:

• Coal spontaneous combustion
• composite inhibitor
• inhibition effect
• chitosan
• procyanidin

Acknowledgements

The authors appreciate the financial support of project No. 51974015 and No. 51474017 provided by the National Natural Science Foundation of China; project No. SMDPC202101 provided by the Key Laboratory of Mining Disaster Prevention and Control (Shandong University of Science and Technology); project No. FRF-IC-20-01 and No. FRF-IC-19-013 provided by the Fundamental Research Funds for the Central Universities; project No. 2018YFC0810601 provided by the National Key Research and Development Program of China; project No. WS2018B03 provided by the State Key Laboratory Cultivation Base for Gas Geology and Gas Control (Henan Polytechnic University); and project No. E21724 provided by the Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines of China (Hunan University of Science and Technology).

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

The work was supported by the National Key Research and Development Program of China [No. 2018YFC0810601]; National Natural Science Foundation of China [No. 51474017]; National Natural Science Foundation of China [No. 51974015]; the Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines of China [No. E21724]; the Key Laboratory of Mining Disaster Prevention and Control [No. SMDPC202101]; the State Key Laboratory Cultivation Base for Gas Geology and Gas Control [No. WS2018B03].