ABSTRACT
A controlled-release inerting inhibitor (CRII) was prepared by embedding the little inhibiting balls (LIB) into the sodium alginate (SA) hydrogel. The water retention and flowability of the SA hydrogel were studied, and the controlled-release effect of the CRII was analyzed by CO2 production rate and scanning electron microscopy. At last, the inhibiting performance and the long-lasting effect of the CRII were investigated. The experimental results show that the 1.5 wt% SA hydrogel has the best water retention and good flowability. Meanwhile, the SA hydrogel also has a great effect on CO2 retention. During the heating process, 88.86% of CO2 produced by the LIB escaped into the air, while only 42.57% of the CRII did. As the temperature gradually increases, a large number of micropores are formed on the surface of LIB, which achieves the controlled-release of inhibitory components. In comparison to the raw coal, the temperature at which CO enters the exponential growth is delayed by 18.8°C for the CRII-treated coal sample, and the release of CO is reduced by 86.3% at 127.8°C. Comparing the CRII-treated coal samples placed for 1 and 8 days, the average inhibition rate of the latter decreased by 0%, −1.81%, 0.56% and 2.59% in four stages (45 ~ 75°C, 75 ~ 100°C, 100 ~ 160°C and 160 ~ 180°C), respectively. The average inhibition rate of the coal samples treated by CRII did not decrease basically before 160°C, while the coal samples treated by NaCl aqueous solution under the same conditions showed a significant decrease in the early stage. In future studies, it is a worthwhile focus that how to optimize the ratio of each component in the LIB and further study the controlled-release performance.
Acknowledgements
The authors deeply appreciate the financial supports provided by Applied Basic Research Project of Shanxi Province, China (No. 20210302123108).
Disclosure statement
No potential conflict of interest was reported by the authors.
Author contribution
Chaoyu Hao: Conceptualization, Supervision, Funding acquisition. Writing – review & editing. Le Li: Methodology, Investigation, Writing – original draft. Ruicong Zhai: Visualization. Yupeng Deng: Validation. Yitong Ma: Resources. Ao Li: Data curation.
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Notes on contributors
Chaoyu Hao
Chaoyu Hao is an associate professor of the Taiyuan University of Technology in China. He obtained his Ph.D from Liaoning technical university, Fuxin. His research interests are centered on the areas of mine fire and gas control, coal mine safety and energy conservation and carbon reduction.
Le Li
Le Li is currently pursuing a master’s degree in Safety Science and Engineering from Taiyuan University of Technology in China. His research interests include mechanism and control methods of coal spontaneous combustion.
Ruicong Zhai
Ruicong Zhai is currently pursuing a master’s degree in Safety Science and Engineering from Taiyuan University of Technology in China. Her research interests include DFT calculation and Catalyst-catalyzed combustion of ventilation air methane.
Yupeng Deng
Yupeng Deng is currently pursuing a master’s degree in Safety Science and Engineering from Taiyuan University of Technology in China. His research interests include detection and control of coal spontaneous combustion.
Yitong Ma
Yitong Ma is currently pursuing a master’s degree in Safety Science and Engineering from Taiyuan University of Technology in China. Her research interest is the effect of calcareous mudstone dust on ventilation air methane in boiler mixed combustion.
Ao Li
Ao Li is a senior laboratory technician of the Taiyuan University of Technology in China. His research interest is centered on the use of polymer materials in coal mines.