低温环境瓦斯扩散试验及不同模型契合度分析

Gas diffusion test in low temperature environment and analysis on compatibility of different models

为了有效治理煤与瓦斯突出灾害,基于瓦斯扩散系数在煤层瓦斯含量测定中的重要性,采用自主研发的含瓦斯煤冷冻响应装置,测定温度为0、-10、-20、-30℃,吸附平衡压力为0.5、1.0、1.5 MPa下的瓦斯解吸扩散量,并对比经典扩散模型和2种动扩散模型与试验数据的契合度。研究结果表明:低温影响煤体表面自由能升高,瓦斯分子热运动能力降低,表现出低温抑制煤中瓦斯解吸扩散;3种扩散模型模拟数据与试验数据对比,2种动扩散模型优于经典扩散模型,且2种动扩散模型中指数函数模型更优于幂函数模型;瓦斯扩散系数受温度影响均经历急速下降和缓慢下降2个阶段。

In order to effectively control coal and gas outburst disasters, given the important role of gas diffusion coefficient in determining coal seam gas content, a self-developed gas-containing coal freezing response device was adopted to measure gas desorption and diffusion capacity at temperature of 0,-10,-20,-30 ℃ and adsorption equilibrium pressure of 0.5, 1.0, and 1.5 MPa. And data of classical diffusion model and two dynamic diffusion models were compared with experimental data. The results show that low temperature affects increase of free energy on coal surface, and thermal movement of gas molecules reduces, indicating that low temperature inhibits gas desorption and diffusion in coal. According to the comparison between simulation data of three diffusion models and experimental data, two dynamic diffusion models are better than classical diffusion model, and their exponential function model is better than power function model. Gas diffusion coefficient undergoes two stages of rapid decline and slow decline under influence of temperature.