Numerical simulation on the methane adsorption characteristics of coal with non-uniform potential well

The kinetics numerical model of methane adsorption in coal was established based on Monte Carlo method, the methane adsorption processes of two kinds of coal models with non-uniform adsorption potential well were calculat- ed,and the methane adsorption characteristics and the variation of adsorption heat under different temperatures and ad- sorption pressures were analyzed. Results show that the isothermal adsorption processes of coal sample models with non-uniform potential well are different from ideal Langmuir curves,and the isobaric adsorption processes can be accu- rately described by negative exponential decay law. The non-uniform distribution characteristics of potential well of coal sample models have effect on the variation of adsorption heat and the sensitivity of adsorption capacity to temperature and adsorption pressure. By curve fitting on adsorption pressure rate b under different adsorption pressures,the iso- therm adsorption equation of non-uniform well is derived. From the physical experiment,it is verified that the isotherm adsorption equation of non-uniform well can provide more accurate description on the processes of methane adsorption in coal than the ideal Langmuir equation.