Pore Damage Properties and Permeability Change of Coal Caused by Freeze-Thaw Action of Liquid Nitrogen

Table 1

Component and basic parameters of coal rocks used in the experiments.

Tests	Parameters/values
Proximate analysis (%)	Mad	Vdaf	Aad	FCad
	3.94	16.52	12.24	67.30
Maceral composition (vol%)	V	I	E	M
	78.26	16.17	4.46	1.11
Elemental analysis (%)	Cdaf	Hdaf	Ndaf	Odaf
	68.80	5.09	1.00	25.11
Basic parameters	Density (g/cm^3)	Elastic module (GPa)	Compressive strength (MPa)	Poisson’s ratio
	1.48	2.35	18	0.28

Note. Proximate analysis was based on the standard of GB/T212-2008. M_ad, moisture, air-drying basis; A_ad, ash yield, air-drying basis; V_daf, volatility, dry ash-free basis; FC_ad, fixed carbon content, air-drying basis. V, vitrinite; I, inertinite; E, exinite; M, minerals.