Experimental Study Of Yang Quan Anthracite's Adsorption-desorption Behavior Of Binary-component Mixtures(N₂-CH₄ )

This paper which in perspective of coal and gas outburst ,based on existing theories, through preparation of coal samples in the laboratory on the adsorption, desorption experiment and numerical simulation of the replacement- desorption of coal seam gas for injection nitrogen to the coal seam and the adsorption-desorption of binary gas have reached the following conclusions:First, the competitive adsorption experiment for the preparation of good coal sample to methane and nitrogen mixture gas show that:mixture gas and its components are well consistent with Langmuir adsorption model .Different proportions of mixed-gas have different adsorption components The injection of nitrogen to the replacement of methane desorption test at the coal methane has been adsorb equilibrium conditions reached the following conclusions: First, although the adsorption capacity of coal to methane is stronger than nitrogen, nitrogen can also replacement methane from the coal-bed due to increased nitrogen's partial pressure in coal-bed. The second is whether the competitive adsorption in mixed gas or injection of nitrogen to the replacement of methane desorption test at the coal methane has been adsorb equilibrium conditions there is the same effect to replacement and desorption coal methane. Through the analysis of the force of coal gas adsorption, adsorption potential and adsorption heat the adsorption potential and the adsorption heat less than methane ,that is to say nitrogen adsorption capacity is lower about methane. However the nitrogen gas mixture reduces the partial pressure of methane,the methane can be displaced from the coal seam.second, the classification of pore in coal can also has been researched. The paper calculated fractal dimensions of the coal sample's pore with using mercury injection test data, and obtained a different stages of coal sample's pore fractal dimension. According to the coal sample's pore fractal laws, the porosity of coal is divided into three categories: infiltration pore, diffusion pore and adsorption pore. These three pores as well as correspond to gas migration in coal-bed.Based on the surface physical-chemistry theory,considering the strain and istromain contraction coupling impacts, established matrix porosity and permeability of theoretical models. On this basis,this paper established injection of nitrogen gas to replacement-desorption coal-bed methane of coal fracture-pore dual-media three-dimensional, non-equilibrium adsorption, steady-state's numerical model. And use of numerical simulation software to solve it. Also analysis the parameters variation such as the coal permeability and the gas content .According to the solver results ,it determined gas injection process parameters such as the injection drilling and the exhaust drilling's spacing and gas injection time. After gas injection at Yangquan mine area test verification, the parameters obtained from the numerical model are more reasonable.