Experimental research on spontaneous oxidization combustion characteristics of coal after pre-adsorption CO2

ABSTRACT

CO₂ is injected into coal bodies in advance so that CO₂ is fully adsorbed in the crack pores of the coal. It can inhibit the combination of coal and oxygen, so as to prevent and control the natural combustion of coal left in goaf. However, domestic and foreign scholars have little research on the low temperature oxidation characteristics and functional group changes of coal after CO₂ pre-injection. In this article, a temperature programmed experimental device is used to analyze the formation of the macro-combustion index gas; a Fourier transform infrared spectroscopy experimental analyzer was determined the content of active functional groups of each component. The results showed that when the coal-sample pre-adsorbed CO₂, the generation trend of CO₂ formed an approximate “V” shape, the oxygen consumption decreased by about 4%. The initial generation temperature of CO and alkane gases is lagged, and the lag temperature is 20 ~ 30°C. CO₂ occupied the surface of the coal surface, and inhibiting the oxidation response of oxygen-containing functional groups. The content of hydroxyl group increases, the oxidative decomposition rate of aliphatic hydrocarbon slows down, and the content of aromatic hydrocarbon increases, which can effectively slow down the course of coal oxidation and spontaneous combustion.

KEYWORDS:

• Coal spontaneous combustion
• inert gases
• low-temperature oxidation
• gaseous product
• active functional group

Acknowledgements

This work was supported by the National Natural Science Foundation of China [grant numbers 52104201, 51974179] and Natural Science Foundation of Shandong Province [grant numbers ZR2020QE131].

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the National Natural Science Foundation of China [51974179,52104201]; Natural Science Foundation of Shandong Province [ZR2020QE131].