Experimental Research On The Influence Of Gas Diffusion Characteristics Of The Low Rank Coal Of Fukang Mining Area By Water

The occurrence of coalbed methane in Xinjiang has the characteristics of large coal seam thickness,numerous coal seam,low coal rank,low coalbed methane content,high permeability and abundant abundance.With the development of coal in Xinjiang gradually increased,frequent coal mine disasters,especially gas disasters,a serious threat to the safety of coal enterprises in Xinjiang production.As one of the common substances in coal mine,water is very important for the gas adsorption and desorption in coal seam.Therefore,it is necessary to study the inhibitiing effect on gas diffusion characteristics oof low-grade coal by water in Fukang mining area of Xinjiang,to make the safty come ture.Five kinds of low-grade coal in Fukang mining area were selected to carry out the related basic experiment:the pore structure of coal samples was measured by nitrogen adsorption method,and the pore structure of coal samples was different.But there was no obvious rule between coal samples.The spontaneous water absorption experiment shows that the TB coal has the best water absorption,and the coal sample of AVEG2130 has the worst.so does The wettability.Finally,the TB and AVEG2130 coal samples were slected,to stduy the effect of water on the gas diffusion characteristics of low-grade coal.The experiment have done by using the self-independent experimental equipment.The experimental results show that the gas content of the coal body will be replaced by the water after entering the coal body.On the one hand,the adsorption capacity of the coal is reduced,which leads to the decrease of the coal dissusion.On the other hand the formation of"capillary" make the path of gas jamed,which leads to the decrease of the speed of gas diffusion.After the end of diffusion process,both tend to a constant value.The influence on coal by water is different,accoding to the metamorphic grade andhydrophilia of coal.The effect of water on the gas diffusion,diffusion rate and diffusion rate of TB coal samples is always larger than that on AVEG2130 coal samples.Since all the diffusion processes in the experiment are transitional diffusion,the method of data fitting can be used to quantitatively calculate the gas diffusion characteristics of coal samples cause the specific form can not be determined.Finally,two formulas are determined to describ the gas diffusion characteristics of low-grade coal.