Jinjitan Coal Mine, Shaanxi Future Energy Chemical Co., Ltd.
School of Safety Science and Engineering, Xi’an University of Science and Technology

为研究亚临界条件（气体压力低于6 MPa和温度低于39 ℃）下CO2在低渗透性原煤中的扩散特性，采用容量法进行CO2的吸附/解吸实验和扩散实验，研究不同温压下CO2在原煤中的吸附/解吸特性和扩散特性。结果表明：压力增大会促进煤体对CO2的吸附，温度升高抑制了煤体对CO2的吸附，CO2在原煤中吸附/解吸过程中存在解吸滞后现象；平衡压力不变时，不同温度下原煤中CO2扩散量与扩散时间成正，CO2扩散速度与扩散时间成反比，CO2扩散系数D随温度的升高而增大；中低压环境下，一定范围内的温度变化（15～35 ℃）对原煤中CO2的扩散速度的影响较小；平衡温度恒定时，不同压力下原煤中CO2扩散量与扩散时间成正比，CO2扩散速度与扩散时间成反比，CO2扩散系数D随压力的升高而增大；温度为15 ℃时，一定范围内的压力变化（0.5～3.5 MPa）对原煤中CO2的扩散速度的影响非常小。

In order to study the diffusion characteristics of CO2 in low-permeability raw coal under subcritical conditions (gas pressure lower than 6 MPa and temperature lower than 39 ℃), the CO2 adsorption/desorption experiments and diffusion experiments were carried out by the volumetric method to study adsorption/desorption and diffusion characteristics of CO2 in raw coal. The results show that the increase of pressure will promote the adsorption of CO2 by coal, and the increase of temperature will inhibit the adsorption of CO2 by coal, and there is a desorption hysteresis phenomenon in the adsorption/desorption process of CO2 in raw coal. When the equilibrium pressure is constant, the diffusion amount of CO2 in the raw coal at different temperatures is positively related to the diffusion time, the CO2 diffusion rate is inversely proportional to the diffusion time, and the CO2 diffusion coefficient D increases with the increase of temperature. Under the medium and low pressure environment, the temperature change within a certain range (15-35 ℃) has little effect on the diffusion rate of CO2 in the raw coal. When the equilibrium temperature is constant, the amount of CO2 diffusion in the raw coal under different pressures is proportional to the diffusion time, the CO2 diffusion rate is inversely proportional to the diffusion time, and the CO2 diffusion coefficient D increases with the increase of pressure; when the temperature is 15 ℃, within a certain range, the pressure change (0.5-3.5 MPa) has very little effect on the diffusion rate of CO2 in the raw coal.

陕西省教育厅一般专项科研计划资助项目（21JK0764）

岳宁，孙伟，代爱萍，等. 亚临界条件下低渗透原煤中CO2扩散特性研究[J]. 煤矿安全，2023，54（9）：15−22

YUE Ning, SUN Wei, DAI Aiping, et al. Study on diffusion characteristics of CO2 in low permeability coal under sub-critical conditions[J]. Safety in Coal Mines, 2023, 54（9）: 15−22