Experimental study on gas desorption of tectonic coal at initial stage

A coal sample test device had been designed for testing the gas desorption velocity and capacities of Pingdingshan and Hebi tectonic coal at initial stage under 30 ℃,different pressures and granularity conditions.In addition,the study had analyzeds the influence factors of tectonic coal gas desorption and established a mathematical model.The results show that the initial desorption velocity of tectonic coal is from 1.23 to 4.20 mL/(g·min),which is 1.36-2.84 times faster than undeformed coal under the same experimental test conditions.In particular,the differences are greater in the first one minute.Tectonic coal gas desorption law is assumed as a monotone increasing power function curve,which can be divided into three stages in the first ten minutes: fast desorption section,slow desorption section and smooth desorption section.The desorption amount of tectonic coal gas in the first 10 minutes occupies 60% of the first one hour.The experimental study results indicate that the initial characteristics of the tectonic coal are detemined by the distribution proportion of macroporous and transitional pores.The desorption velocity increases with particle size,which is not obvious when it is below the limit grain size.The desorption velocity and adsorption equilibrium pressure can be described as power-exponential function relationship.The desorption curve of tectonic coal gas at initial stage satisfies the K.Winter expressions.