颗粒煤负压解吸扩散特征参数研究
Study on Characteristic Parameters of Particulate Coal Gas Desorption and Diffusion Under Negative Pressure Environment
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摘要: 为了研究颗粒煤负压解吸扩散特征参数,采用自制颗粒煤瓦斯负压解吸实验系统,模拟负压取样过程初期负压阶段瓦斯解吸扩散规律,研究颗粒煤不同吸附平衡压力(0.5、0.74、1 MPa)在不同负压(-40、-50、-60 kPa)下解吸扩散规律,并基于第三类边界条件经典扩散模型分析了颗粒煤瓦斯负压解吸扩散特征参数。研究结果表明:负压环境下颗粒煤瓦斯极限瓦斯解吸量随着环境负压值的增大而增加,随着吸附平衡压力的升高极限瓦斯解吸量的增幅变小;同一吸附平衡压力下,随着负压值的增大,传质毕欧准数和传质傅立叶准数随之增大,负压值越大颗粒煤外部对流传质阻力越小,扩散场扰动波及的深度越深入煤粒内部;同一吸附平衡压力下扩散系数随着负压值的增大而增大,同一负压值下随着吸附平衡压力的增大而减小,负压值增大改变了瓦斯解吸动力学参数,加快了瓦斯解吸扩散。Abstract: In order to study the characteristic parameters of particulate coal gas desorption and diffusion within a negative pressure environment, a self-made particulate coal gas desorption experimental system was used to simulate the law of gas desorption and diffusion in the initial negative pressure stage of the negative pressure sampling process, and to study the particulate coal at different adsorption equilibrium pressures (0.5 MPa, 0.74 MPa and 1 MPa) and different negative pressures (-40 kPa, -50 kPa and -60 kPa) gas desorption and diffusion laws, and based on the classical diffusion model of the third kind of boundary conditions, the characteristic parameters of gas desorption and diffusion are analyzed. The research result shows that the ultimate gas desorption capacity of particulate coal increases with the increase of the negative pressure value of the environment, and the ultimate gas desorption capacity increases with the increase of the adsorption equilibrium pressure and rate of increase becomes smaller; under the same adsorption equilibrium pressure, with the increase of the negative pressure value, the mass transfer Biotherm and the mass transfer Fourier increase accordingly. The larger the negative pressure value, the smaller the external convective mass transfer resistance of particulate coal, the depth of the disturbance of the diffusion field goes deeper into the coal particles; the diffusion coefficient increases with the increase of the negative pressure value under the same adsorption equilibrium pressure, and decreases with the increase of the adsorption equilibrium pressure under the same negative pressure value, and the
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