Experimental Study On The Effect Of Surfactant On The Gas Desorption Of Coal

With the increase of coal mining depth and production,gas disasters and gas outburst accidents have become more and more serious,which has made great troubles for safety production of coal mine.At present,one of the most effective measures to solve the problem is suppressing gas desorption by injecting water.Water is not easy to completely wet the coal body and the effect of suppression desorption is poor.Therefore,the influence of surfactant on gas desorption has been studied by injecting surfactants in this paper.In this paper,two kinds of anionic,cationic and nonionic surfactants were selected to study surface wettability on coal and adsorption rules.Results show that contact angle,adhesion tensionand adhesion work of six surfactants on the surface of coal samples increase first and stabilize then as the concentration increases and it can completely spread on surface of coal,but the spreading performance of cationic is weak.The rules of relative increment for contact angle,spreading coefficient,adhesion tension and adhesion work are obviously.The surfactant concentration is positively correlated with the zeta potential.The gas desorption experiment has been carried for dry coal and coal infiltrated by pure water,single surfactant solution and salted compound solution.The desorption amount has been tested and changing relationship of desorption rate with time has been calculated.The rule of desorption amount and rate influenced by single surfactant solution and salted compound solution has been got.Results show that gas desorption amount and rate of coal are decreased by four kinds of surfactant solution and two kinds of salted compound solution.In other words,All of them have the effect of inhibiting gas desorption from coal samples.Compared dry coal and coal infiltrated by pure water,The maximum amount of gas desorption and the maximum rate of gas desorption are positively correlated with the concentration of single surfactant,and negatively correlated with the concentration of SDBS in mixture solution.desorption amount of coal has been fitted by four kinds of kinetic fitting model,and fitting curves and kinetic parameters have been obtained from them.The changing rules of kinetic parameters influenced by concentration of single surfactant and ratio of mixture solution also have been obtained.Results show that the fitting degree of three kinds of kinetic models is poor compared to the parabolic model.Desorption rate constants k1 and k2,equilibrium desorption quantities Q1 and Q2 are positively correlated with the concentration of single surfactant,and negatively correlated with the concentration of SDBS in mixture solution.