Experimental analysis of the pore structure and fractal characteristics of different metamorphic coal based on mercury intrusion‑nitrogen adsorption porosimetry

Abstract

The pore structure of different metamorphic coal was analyzed by mercury intrusion porosimetry and N2 adsorption. Combined with the fractal dimension models of the Frenkel-Halsey-Hill and Menger, the pore size range of the experiment was spliced reasonably. A new pore classification scheme is put forward by fractal dimensions, revealing the pore structure and fractal characteristics of different metamorphic coal. The results suggest that pores exhibit piecewise fractal characteristics. A new pore classification scheme is put forward by piecewise fractal dimensions: I (0–2.0 nm, corresponding to D1); II (2.0–50 nm, corresponding to D2); III (50–2000 nm, corresponding to D3); IV (2000–20,000 nm, corresponding to D4); V (>20,000 nm, corresponding to D5). It is not inconsistent with the international union of pure and applied chemistry for pore classification, which shows that the new pore classification scheme is reliable.