Damage characteristics of pulverized coal under different gas pressures in coal and gas outbursts

ABSTRACT

Coal and gas outbursts are complex dynamic phenomena and are highly hazardous. This article established an experimental system to research the damaging effect of gas on particulate coal during coal and gas outbursts, which replicated the outburst scenario by instantaneously releasing different-pressure gas. The results show that the higher the gas pressure is, the larger the new surface area is, and the gas damages the pulverized coal more drastically. The mass ratio of new granular size coal is between 8–27%. The surface area increased significantly (73.0%-245.2%). The mean order of increasing surface area is SC (1.102 m²)> DC (0.9875 m²)> SN (0.8999 m²)> DN (0.8369 m²), which indicates that the extent to which gas destroys particulate coal is inversely proportional to the solidity coefficient and positively proportional to the adsorptivity. The ability of weakly adsorbable gases to break particulate coal is more affected by gas pressure. The degree of breakage of low-firmness coals is more responsive to gas pressure. The percentage of coal mass broken by gas is positively correlated with gas pressure and adsorptivity and negatively correlated with the firmness coefficient. Finally, the quick release of gas occurs in three stages: an acceleration section (0–0.05 s), a high-speed section (0.05–0.15 s), and a deceleration section (after 0.15 s).

KEYWORDS:

• Gas with different pressure releases
• gas damage to particulate coal
• evaluation of coal particulate damage
• the surface area of particulate coal
• adsorption and desorption

Acknowledgments

This work was financially supported by the Research and Demonstration of Cloud Warning Technology for Gas Disasters Driven by Multidimensional Data (Qiankehe Support [2021] General 514), Fundamental Research Funds for the Central Universities (2021YJSAQ06), and the National Natural Science Foundation of China (52004292). These supports are greatly acknowledged and appreciated.

Disclosure statement

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

Data availability statement

Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

The work was supported by the National Natural Science Foundation of China [52004292]; Fundamental Research Funds for the Central Universities [2021YJSAQ06]; Guizhou Provincial Science and Technology Projects [[2021] General Projects 514].