Experimental study on desorption diffusion characteristics of coalbed methane under real time electric field loading

In order to explore the desorption diffusion characteristics of coalbed methane under real-time electric field loading and reveal the effect of electric field on efficient extraction of coalbed methane, the desorption diffusion test system of coal under controllable electric field strength was designed and developed independently. The desorption diffusion characteristics of CH₄ and CO₂ in coal under electric field loading were investigated experimentally, and the diffusion coefficient under each electric field strength was calculated by power function diffusion model. The results show that: under the real-time loading of electric field, the desorption capacity of coal is improved to a certain extent, but the influence of electric field on the desorption capacity of CO₂ is more obvious. At the same time, the electric field can strengthen the initial desorption speed of coal gas. Compared with no electric field, the initial desorption speed of CH₄ increases by 6.9%, 15.3%, 14.6% when the characteristic field strength is 30, 60, 90 kV/m, and the CO₂ increases by 3.4%, 6.7%, 9.2%; on the other hand, the results of power function diffusion of CH₄ in coal under electric field loading show that the diffusion model can be highly consistent with the experimental values, and the diffusion coefficient increases with the increase of the loading field strength. The electric field is conducive to the desorption and diffusion of methane in coal.