Experimental Study on Fractal Characteristics of Adsorption Pore Structure of Coal

The adsorption pore structure is the key affecting technology of enhanced coal bed methane recovery (ECBM). In this paper, nitrogen measurement (NAM) and low-field nuclear magnetic resonance (NMR) methods are used to test structural parameters pores four samples with different metamorphic degrees. Combining fractal theory, applicability physical significance dimensions obtained from models analyzed. Finally, main factors complexity size influence characteristics on properties discussed. results show that increase in degree metamorphism, ranking order volume specific surface area long flame > anthracite gas coking coal. dimension D2 calculated by Frenkel–Halsey–Hill (FHH) model ranges 2.5 2.9, representing irregularity, D3 FHH 2.004 2.037, distribution. There no clear quantitative relationship between single pores. more diameter distribution concentrated range 2–5 nm, larger is, higher is; D2, which represents irregularity coal, has a good linear positive correlation maximum capacity N2.