Effect of microwave irradiation on pore and fracture evolutions of coal
LI He
LIN Baiquan
HONG Yidu
YANG Wei
LIU Tong
HUANG Zhanbo
WANG Rui
Abstract：To reveal the impact of microwave energy on the pore and fracture structure of coal,a cyclic microwave irradiation experiment was designed.Pore and fracture evolutions of coal under different exposure durations were investigated using infrared thermal imaging,ultrasonic wave detecting,nuclear magnetic resonance and computer tomographic scan.The results show that microwave exerts pore-opening,pore-dredging and pore-collapsing effects on coal,among which pore-opening and pore-dredging effects are dominant.Microwave irradiation enlarges the total pore volume and pore connectivity.The irreducible porosity and producible porosity increase 30.3％ and 167.9％,respectively.Different components in coal exhibit heterogeneous microwave absorption property and thus were heated asynchronously.The nonuniform heating induces thermal stresses,which laniate existing fractures and induce new fractures.As a resuit,the NMR permeability increase and the ultrasonic wave velocity decrease.The microfractures in the coal first increase and then evolve to larger fractures to form fracture network.
Keywords：microwaveporefracturenuclear magnetic resonancecomputer tomographic scan
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：8( 1194-1201 )