Development and application of multi-field coupled seepage desorption experimental system for gas-containing coal

Abstract

In order to improve the experimental research basis under gas coal field coupling condition, we independently developed gas coal field coupling seepage desorption experimental system which mainly composed of constant pressure automatic inflatable adsorption unit, coal gas “surface diffusion” seepage device, gas extraction unit, stress and unloading unit, contactless strain measurement unit, acoustic emission monitoring unit, multi-parameter monitoring unit and experimental system management software. The experiment of coal methane adsorption and the stress-strain-permeability law of gas-bearing coal during loading were studied. The study shows that both the adsorption and desorption of the coal body fit the exponential function; the desorption rate first increases rapidly and slowly increases and finally reaches the equilibrium state; at the same time, with the decrease of the particle size, the shorter the coal adsorption equilibrium time, the greater the desorption rate and the total desorption amount; stress-strain-penetration process of gas-bearing coal shows a stage characteristic, coal body permeability decreases rapidly during the compaction stage, the strain increases rapidly during the elastic deformation stage, the permeability slowly decreases and reaches a minimum; permeability was slowly increased during the yield phase, and the permeability increases rapidly in the post-peak softening stage.

Keywords

• multi-field coupling
• gas seepage
• stress-strain
• acoustic emission
• experimental system