Simulation of Microwave's Heating Effect on Coal Seam Permeability Enhancement

Abstract

As hydraulic fracturing was forbidden in some countries due to possible negative environmental impacts and enhanced coalbed methane (ECBM) was restricted by in-situ conditions, microwave heating was proposed to enhance coalbed permeability. One of the mechanisms of improving coal permeability with microwave irradiation is that thermal expansion caused by microwave heating. To study the influence of microwave's heating effect of coal samples, the simulations were conducted using a coupled electromagnetic, thermal and mechanical model in this paper. The temperature, Von-Mises stress and strain distribution of coal sample are recorded every 10 s. The permeability distribution is also obtained based on the relationship between strain and permeability from articles. It was found that volume average temperature, stress, strain and permeability increase almost linearly with time. The average permeability increased from 1.65 x 10-16 m2 to 3.63 x 10-16 m2 under 2.45 GHz and 500 W microwave radiation after 300 s. The significant increase proved microwave to be effective in coal seam permeability enhancement.

Department(s)

Mining Engineering

Keywords and Phrases

Coal; Coal deposits; Computer simulation; Environmental impact; Methane; Microwave heating; Stress-strain curves; Thermal expansion; Thermal stress; Average permeability; Coal permeabilities; Coal seam permeability; Coalbed permeability; Comsol multiphysics; Permeability distribution; Permeability enhancement; Permeability increase; Microwave irradiation; COMSOL Multiphysics; Numerical simulation

International Standard Serial Number (ISSN)

2095-2686; 2589-062X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 China University of Mining & Technology, All rights reserved.

Publication Date

01 Sep 2019

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