Title: Analysis of the methane diffusion kinetics in tectonic coal under cyclic loading

Authors: Chengwu Li; Honglai Xue; Po Hu; Cheng Guan; Wenbiao Liu

Addresses: School of Resource and Safety Engineering, China University of Mining and Technology, Beijing 100083, China ' School of Resource and Safety Engineering, China University of Mining and Technology, Beijing 100083, China ' School of Safety Engineering, Shenyang Aerospace University, Shenyang 110136, China ' School of Resource and Safety Engineering, China University of Mining and Technology, Beijing 100083, China ' School of Resource and Safety Engineering, China University of Mining and Technology, Beijing 100083, China

Abstract: Cyclic loading influences coal permeability and methane production. Experiments examining methane diffusion in a tectonic coal were performed at an adsorption equilibrium pressure of 0.6 MPa over a range of stresses from 0 MPa to 16 MPa. The results show that the methane diffusion in a coal matrix under cyclic loading can be modelled by a power-langmuir model, Qt = ati / (1 + bti). The parameters a, b and i are demonstrated to be related to the effective diffusion coefficient in the unipore model. The ultimate diffusion amount tended first to decrease, rise rapidly and finally decline again with increasing loading stress. The methane diffusion rates under several loading stresses exhibited three stages: rapid attenuation, slow attenuation and steady diffusion. Both the initial diffusion rate and the attenuation coefficient of the diffusion rate fluctuated slightly at first, increased steeply, and finally dropped as the stress increased. [Received: March 2, 2017; Accepted: October 24, 2017]

Keywords: coal mine methane; CMM; tectonic coal; cyclic loading; diffusion model.

DOI: 10.1504/IJOGCT.2018.091550

International Journal of Oil, Gas and Coal Technology, 2018 Vol.18 No.1/2, pp.218 - 238

Available online: 26 Apr 2018 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article