Investigation on Pore Structures of a Medium Volatile Bituminous Coal with Solvent Extraction Tests

Abstract

This paper presents an experimental investigation on the changes of pore structures, pore morphology of a medium volatile bituminous coal through solvent extraction under ultrasonic irradiation. The solvent extraction experiments, carried out using four non-or weak-polarity solvents with the twice-and thorough-extraction methods, provided a series of extract residues for comparison study on the coal pore structure with reference to the coal sample. Scanning electronic microscopy (SEM) and mercury injection porosimetry (MIP) were used to study the morphological and structural changes of pores both the coal samples and the residues. The results show that most solvable organic components can be extracted from coal through twiceextraction method with the solvents used in this study; under the ultrasonic irradiation, the solvent extraction makes the surfaces of coal particles grow loose and thus come to pieces forming many intergranular pores. And the numbers of intergranular pores have a tendency to increase as the extraction degree increases; the solvent extraction produced the "pore expansion" effect and increased opening pores, and hence can improve the connectivity among pores and make the pore distribution more uniform.

Estimation of Nanoporosity of ZSM-5 Zeolites as Hierarchical Materials

“…There are some significant differences in the form of α S -plots as a function of MR, mainly for Z120. A pronounced distortion of the isotherm shape is observed at a very low p/p 0 , which can be explained by the enhancement of the sorbent-sorbate interaction in the pores of molecular dimensions, that is, the process of micropore filling [18]. This type of α S -plot is characteristic of microporous adsorbents having a wide range of pore sizes and results in two or more separate stages of micropore filling.…”

Response of Methane Diffusion in Varying Degrees of Deformed Coals to Different Solvent Treatments

“…Coal is considered a threedimensional macromolecule composed of condensed aromatic nuclei containing functional groups and side chains that can be soluble in organic solvents 8 . Removal of soluble organic fractions in coal produce porous and cause physical, chemical and adsorption changes [9][10][11][12][13] . Considering the fact that changes in pore structure are closely related to methane diffusion, diffusion performance after organic solvent extraction is imperative to research.…”

The gas content distribution of coal reservoir at the Changzhi block, south-central Qinshui Basin, North China: Influences of geologic structure and hydrogeology

“…As an unconventional natural gas resource, coalbed methane (CBM) can remedy to the shortage of conventional gas resource and is now large-scalely explorated and exploitated in the world (Colosimo et al., 2016; Moore, 2012). In coal reservoir, methane is primarily adsorbed at the surface of the coal matrix micropores and is limited from desorbing by the reservoir pressures (Moore, 2012; Tao et al., 2018; Zhang et al., 2013), where the gas in the conventional reservoir is either free state or dissolved. Therefore, the accumulation mechanism for CBM is quite different from that of conventional gas reservoirs, which largely depends on the favorable combination of the right properties of the coal, an adequate pressure regime, and the depositional, structural, and hydrogeology settings (Ayers, 2003; Bustin and Clarkson, 1998; Kaiser, 1994; Scott, 2002; Song et al., 2012), of which the geologic structure and hydrogeology may be determinant for some basins (Kaiser, 1994; Pashin and Groshong, 1998).…”