基于巨正则蒙特卡罗和分子动力学方法的多元气体在气肥煤中的竞争吸附研究OA

To investigate the occurrence characteristics of CH4,CO2,and H2S in gas-fat coal,reveal their adsorption kinetic pro-cesses in gas-fat coal at different temperatures and the microscopic mechanism of competitive adsorption among the three gases un-der different volume fractions,the competitive adsorption of binary mixtures(CH4/H2S and CO2/H2S)in coal seams was studied us-ing Grand Canonical Monte Carlo(GCMC)and molecular dynamics(MD)methods under conditions of 273.15-313.15 K and 0-3 MPa.The influences of volume fractions on gas adsorption capacity,isosteric heat of adsorption,energy distribution,selectivity coef-ficient,and probability density distribution were analyzed.The results show that the order of gas adsorption capacity in coal from high to low is H2S>CO2>CH4.The adsorption kinetics of CH4,CO2,and H2S agree well with the pseudo-second-order kinetic mod-el,with average fitting degrees of 0.993 0,0.999 7,and 0.999 8,respectively.At adsorption equilibrium,the adsorption capacity gradually decreases with increasing temperature,while the second-order adsorption rate constant k2 first decreases and then increases with rising temperature.When the volume fraction of CH4 increases from 10％to 90％,the saturated adsorption capacity of CH4 rises from 1.86 cm3/g to 7.89 cm3/g,while that of H2S decreases from 41.54 cm3/g to 28.71 cm3/g.As the volume fraction of CO2 in-creases from 10％to 90％,the saturated adsorption capacity of CO2 increases from 6.64 cm3/g to 26.66 cm3/g,whereas that of H2S decreases from 36.17 cm3/g to 10.86 cm3/g.The adsorption selectivity coefficients of the CH4/H2S and CO2/H2S binary systems de-cay exponentially with increasing equilibrium pressure:they decrease rapidly at first,then slowly,and finally tend to be stable.