Application And Experiment Study On Technology For Increasing The Permeability Of Coal Seam By Impactling With High-energy Air

In this paper, according to the characteristic of soft coal seam with lowpermeability in most coal mines, the technology and equipment are studied toincrease the permeability of coal seam. Through testing the coal seam destructionwith shock wave of high-energy air, the gas movement law and destructionquantity are studied for different coal bed. Simultaneously, through developing theunderground mobile pump station with air, a series of equipment and technology areprovided to increase the permeability of coal seam and improving the gas extractionefficiency, and the difficulty is overcame to extract the gas in the low permeability coalseam. The gas extraction efficiency is increased40%~50%for the low permeabilitycoal seam. It provides technical support for preventing serious and extraordinary safetyproduction accidents from occurrence and pushing the stable development of the safetyproduction situation.Firstly, based on the previous research results and coal seam gas occurrence andflow theory, the characteristics of the high pressure air impacting coal seam and theprocess of increasing the permeability are discussed and analyzed in detail.30groups ofcoal sample are selected from Haizhou coal mine and Aiyou coal mine of Fuxin MiningGroup, and10team compression tests and20gas explosion of coal samples withhigh-pressure are conducted experiment. The permeability of coal samples arecalculated before and after gas explosion by recording the coal sample physicalparameters and experimental parameters.Studies show that:(1) The coal sample permeability increasing overall after gas explosion, an average increasemore than81%.(2) The greater the pressure of high pressure gas is, the greater the incremental of thepermeability of the coal sample after gas explosion is. Based on the increment of thepermeability of the10groups of coal sample from Haizhou coal mine after gas explosion andgas explosion pressure, through regression analysis, the relationship between incremental of thepermeability after coal sample gas explosion and gas pressure is a power function.(3) The increment of the permeability after gas explosion is larger for harder coal. Secondly, according to the coal deformation, rupture basis and the basic principleof seepage mechanics, the coupling mathematical model is presented involving coaldeformation, rupture and gas flow. And the numerical simulation software is developedbased on the coupled mathematical model, the schemes before and after the actualimpact with high pressure are compared, analyzed and evaluated.Finally, based on the introduction of high pressure air compressor in the seconddevelopment, the high pressure air single point and multipoint release devices aredeveloped by improving the driving way and explosive-proof grade, and thetechnological experiment is conducted to increase the permeability of coal seamunderground the coal mine. It provides a new method for low permeability coal seamimproving gas extraction efficiency.The study is the first test based on high energy air blasting, shock, and breakingcoal at home and abroad. The increasing permeability technology and equipment used toenhance gas extraction are developed for the low gas permeability coal seam. Thestudied results obtained an invention patent, namely "The gas pre-drainage method andequipment breaking coal body with high-pressure gas". The engineering application testachieved good effect in Xin’an coal mine of Shuangyashan Mining Group. Therefore thedrainage problem of low permeability coal seam is solved, and the gas drainage rateincreased from40%to50%for the low permeability coal seam. It provides technicalsupport for preventing serious and extraordinary safety production accidents fromoccurrence and pushing the stable development of the safety production situation.