Testing Study About Overall Gas Desorption Process Of Gas-containing Coal Under Different Particle Size And Different Metamorphic Grade

System research about gas desorption law has great significance and practical value of accurating prediction of coal and gas outburst hazard,prevention and control of gas accidents.Large flow and fast speed and great changes are the characteristics of the initial desorption gas course,while dramatic decrease but continuous are the characteristics of gas emission in later period,because of restriction of traditional measuring technology,comprehensive measurement of overall gas desorption process of gas-containing coal can't be achieved up to now.We study gas desorption law of gas-containing coal at present,gas desorption law is measured when gas pressure of coal sample tank is reduced close to atmospheric pressure,which initial desorption gas always ignored.When coal-body is destructed and gas desorption is occurred in the process of digging,a large number of gas is discharged from coal in the initial stage,which include free and adsorbed gas,which play an important role in promoting development of coal and gas outburst,it determines whether coal and gas outburst occurred or not and strength of coal and gas outburst,after that the effect of slow-released numerous gas on coal and gas outburst is rapidly decreasing,also the quantitative relationship research between gas desorption law,which is obtained from overall gas desorption process of gas-containing coal,and coal and gas outburst has seldom been studied.This paper aim at the flaws of the gas desorption law research,the test platform of overall gas desorption process of gas-containing coal was constructed,which is based on the measuring device of expansion energy of initial released gas.The influence on overall gas desorption law of factors such as adsorption equilibrium pressure and particle size and metamorphic grade were tested in the laboratory,which obtaining curve of overall gas desorption law under different influence conditions,the above rule is analyzed in theory.Using logarithmic function and power function fitting respectively curve of overall gas desorption law under different influence conditions,Founding that the power function is more suitable to describe overall gas desorption law of gas-containing coal.Gas desorption law of outburst coal is analyzed,difference of gas desorption law between outburst situation and non-outburst situation is researched,which is the amount of gas desorption in preliminary stage.So expansion energy of initial released gas index is superior to drilling cuttings weight and gas desorption K1 and drilling cuttings weight and gas desorption ?h2 when choosing outburst prediction index.In addition,using equation fitting respectively relationship of gas desorption quantity of coal particles in different periods and expansion energy of initial released gas.Outburst critical value of gas desorption quantity of coal particles in different periods is calculated,which has great importance and significance in predication and forecastion of coal and gas outburst.