Evolution Law of Adsorption and Desorption Characteristics of CH4 in Coal Masses during Coalbed Methane Extraction
MetadataShow full item record
The low-temperature oxidation of coal during coalbed methane extraction is inevitable. To study the evolution of the CH4 adsorption and desorption characteristics in coal masses during the low-temperature oxidation of coal, starting from the evolution of physical and chemical adsorption of CH4 in coal masses during the low-temperature oxidation of coal and combining it with the evolution of free radicals, we constructed a physical model of CH4 adsorption and desorption in the coalbed methane extraction process. This model provides the theoretical basis for improving the efficiency and quantity of coalbed methane extraction. Our results indicate that during coalbed methane extraction, the mesopores, macropores, and overall porosity increase with the rise in oxidation temperature. However, the number of micropores first increases and then decreases during the process, leading to the CH4 physical adsorption capacity showing a trend of first increasing and then decreasing with increasing oxidation temperature; however, the number of -COOH groups shows the opposite trend to that of the number of micropores, resulting in the CH4 chemical adsorption capacity first decreasing and then increasing with the increase of the oxidation temperature; meanwhile, the free radical content increases gradually with the increasing oxidation temperature, leading to the continuous consumption of O2 adsorbed on the coal surface and the reinforcement of the CH4 adsorption capacity. To maximize coalbed methane extraction efficiency, it is necessary to take measures to avoid the low-temperature oxidation of coal at the initial stage.
Showing items related by title, author, creator and subject.
Experimental investigation on variation of physical properties of coal particles subjected to microwave irradiationHu, G.; Yang, N.; Xu, Guang; Xu, J. (2017)The gas drainage rate of low-permeability coal seam is generally less than satisfactory. This leads to the gas disaster of coal mine, and largely restricts the extraction of coalbed methane (CBM), and increases the emission ...
Feng, G.; Wu, Y.; Zhang, C.; Hu, S.; Shao, H.; Xu, Guang; Ren, X.; Wang, Z. (2017)© 2017 Elsevier Ltd. Coal spontaneous combustion is a natural hazard during mining. In China, the longwall gob area is the main places that are prone to coal spontaneous combustion due to excessive residual coal in the ...
Characterization of Pore Structures with Mercury Intrusion Porosimetry after Electrochemical Modification: A Case Study of Jincheng AnthraciteGuo, J.; Zhang, X.; Lu, Chunsheng ; Chai, Z.; Kang, G.; Zhao, G.; Kang, T.; Zhang, S.; Li, H. (2021)Quantitative characterization of the change in the cleat and pore structures and fractal dimensions in anthracite after electrochemical modification is crucial for better understanding of the modification effect. Thus, ...