Theoretical and experimental study on secondary crushing induced by rapid desorption of coal particle gas during coal and gas outburst process

TU Qingyi; SUN Haoyu; YUAN Liang; XUE Sheng; CHENG Yuanping; AN Fenghua; LI Wei; WANG Liang

doi:10.13247/j.cnki.jcumt.20250020

Abstract：To investigate the secondary crushing of coal particles induced by rapid gas desorp-tion during during the outburst process,a theoretical model known as the"popcorn"effect was established,and the numerical simulations of rapid gas desorption in coal particles were con-ducted.Using a self-designed experimental apparatus for studying secondary crushing of coal particles,this paper examined the influences of adsorption equilibrium pressure,coal's me-chanical strength,and structural characteristics on secondary crushing.Additionally,the role of secondary crushing of coal particle induced by rapid gas desorption in coal and gas outbursts was discussed.The results indicate that there exists a critical mechanical strength threshold for secondary crushing of coal particle induced by rapid gas desorption under a certain gas pres-sure.The mechanical strength of coal is negatively correlated with the crushing rate and posi-tively correlated with the average particle size of the crushed coal.The crushing rate of the Nu-odong coal sample reaches 11.960％to 23.317％,significantly higher than that of other coal samples.Moreover,the average particle size of the Nuodong coal sample after crushing is only 55.419 to 76.469 pm,which is markedly smaller than that of other coal samples.As the ad-sorption equilibrium pressure increases,the driving force for secondary crushing intensifies,leading to a significant increase in the crushing rate and a noticeable refinement trend in the av-erage particle size of the crushed coal.When the adsorption equilibrium pressure rises from 3.0 MPa to 5.0 MPa,the crushing rates of the four different coal samples increase by 5.927％to 11.461％,while the average particle sizes of the crushed coal decrease by 27.252％to 41.562％after the experiments.Compared to intact coal with relatively intact apparent struc-tures and high mechanical strength,tectonic coal,which exhibits a cemented apparent struc-ture and low mechanical strength,is more prone to secondary crushing due to rapid gas desorp-tion.The research findings contribute to unveiling the transportation process and catastrophic mechanism during the development stage of coal and gas outbursts.