Desorption and diffusion characteristics of methane in the non-ventilation working face

Gao, Tao; Deng, Cunbao; Han, Qing

doi:10.1016/j.fuel.2022.124884

Cited by 1 publication

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“…The desorption amount of high-rank ZG is much larger than that of the other four kinds of coal samples, and the desorption amount of low-rank TS is larger than that of XS, XJW, and HYC. By analyzing the shortcomings of the Langmuir equation in describing the positive pressure desorption curve, a previous study proposed an extended Langmuir EXT1 model, which slowed down the influence of time on the desorption quantity by attaching an index to the independent variable, thus improving the fitting accuracy of the model. The Langmuir EXT1 model is as follows Q t = Q ∞ K T 1 − μ 1 + K T 1 − μ where Q t is the methane desorption volume in mL/g; Q ∞ is the ultimate methane desorption volume in mL/g; T is the time in s; and K and μ are the model parameters.…”

Section: Resultsmentioning

confidence: 99%

Experimental Study on the Properties of Gas Diffusion in Various Rank Coals under Positive Pressure

et al. 2023

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A kind of closed mining and nonventilation working face is proposed, which provides a possibility for eliminating coal mine accidents and extracting high-purity gas. During mining, a confined space above normal pressure is formed in the face. Geological conditions cause significant differences in the physicochemical properties of coal and affect the occurrence and migration of gas in coal seams. The pore structures of five coal samples were obtained by mercury injection and low-temperature nitrogen adsorption. The self-made positive pressure desorption experimental device was used to conduct isothermal desorption experiments under different environmental pressures. An extended Langmuir model was proposed to carry out regression analysis on the curve of positive pressure desorption with time. The effect of coal pore structure on gas diffusion properties was discussed. The results indicate that the development degree of micropores in coal determines the amount of gas adsorption. With the increase of coal rank, both the ultimate desorption quantity and desorption rate first decrease and then increase. The positive pressure enhances the concentration of methane outside the coal and inhibits methane diffusion. With an increase of positive pressure, the desorption capacity of the high-rank ZG was significantly inhibited, and the desorption limit and initial desorption rate decreased by 15.80–44.54 and 16.92–47.93%, respectively. The diffusion coefficient of the middle-rank XS has the greatest decrease rate of 1.56–18.05%. The pore structure of coal is the essential reason that affects methane diffusion.

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