Comprehensive Fractal Description of Porosity of Coal of Different Ranks

Table 7

Calculation results of fractal dimension of coal sample pore distribution obtained by liquid nitrogen adsorption method.

Sample number	Aperture range (nm)	Linear fitting equations of different aperture segments	𝑅^2	𝐾	𝐷2
Number 1	100≦𝑑≦326.60	𝑦1=−0.2501𝑥−0.1771	0.9878	−0.2501	2.7499
	10≦𝑑<100	𝑦2=−0.3938𝑥−0.3987	0.9994	−0.3938	2.6062
	2.03≦𝑑<10	𝑦3=−0.3362𝑥−0.1539	0.9977	−0.3362	2.6638
Number 2	100≦𝑑≦361.14	𝑦1=−0.2548𝑥−0.5960	0.9969	−0.2548	2.7452
	10≦𝑑<100	𝑦2=−0.4473𝑥−0.8511	0.9997	−0.4473	2.5527
	2.03≦𝑑<10	𝑦3=−0.3615𝑥−0.4884	0.9963	−0.3615	2.6385
Number 3	100≦𝑑≦248.31	𝑦1=−0.0822𝑥+2.5891	0.9537	−0.0822	2.9178
	10≦𝑑<100	𝑦2=−0.0717𝑥+2.5791	0.9980	−0.0717	2.9283
	2.05≦𝑑<10	𝑦3=−0.0757𝑥+2.5721	0.9972	−0.0757	2.9243
Number 4	100≦𝑑≦338.64	𝑦1=−0.4215𝑥+0.4420	0.9300	−0.4215	2.5785
	10≦𝑑<100	𝑦2=−0.1813𝑥+0.6536	0.9956	−0.1813	2.8187
	2.03≦𝑑<10	𝑦3=−0.1418𝑥+0.8023	0.9999	−0.1418	2.8582

Note: the “𝑅²” is coefficient of correlation, the “𝐾” is slope, and the “𝐷₂” is fractal dimension of pore volume (liquid nitrogen adsorption method).