Experimental evaluation of ultrasound treatment induced pore structure and gas desorption behavior alterations of coal

Tectonic coals in coal seams may affect the process of enhanced coalbed methane recovery with CO2 sequestration (CO2-ECBM). The main objective of this study was to investigate the differences between supercritical CO2 (ScCO2) and intact and tectonic coals to determine how the ScCO2 changes the coal’s properties. More specifically, the changes in the tectonic coal’s pore structures and its gas desorption behavior were of particular interest. In this work, mercury intrusion porosimetry, N2 (77 K) adsorption, and methane desorption experiments were used to identify the difference in pore structures and gas desorption properties between and intact and tectonic coals after ScCO2 treatment. The experimental results indicate that the total pore volume, specific surface area, and pore connectivity of tectonic coal increased more than intact coal after ScCO2 treatment, indicating that ScCO2 had the greatest influence on the pore structure of the tectonic coal. Additionally, ScCO2 treatment enhanced the diffusivity of tectonic coal more than that of intact coal. This verified the pore structure experimental results. A simplified illustration of the methane migration before and after ScCO2 treatment was proposed to analyze the influence of ScCO2 on the tectonic coal reservoir’s CBM. Hence, the results of this study may provide new insights into CO2-ECBM in tectonic coal reservoirs.

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Experimental evaluation of catalyst layers with bimodal pore structure for Fischer–Tropsch synthesis

Catalysis Today ◽

10.1016/j.cattod.2015.11.009 ◽

2016 ◽

Vol 275 ◽

pp. 155-163 ◽

Cited By ~ 7

Author(s):

Henning Becker ◽

Robert Güttel ◽

Thomas Turek

Keyword(s):

Pore Structure ◽

Experimental Evaluation ◽

Tropsch Synthesis ◽

Fischer Tropsch ◽

Fischer Tropsch Synthesis ◽

Catalyst Layers ◽

Bimodal Pore Structure

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Influence rules and mechanisms of mechanical vibration at different frequencies on dynamic process of gas diffusion from coal particles

Energy Exploration & Exploitation ◽

10.1177/01445987211013538 ◽

2021 ◽

pp. 014459872110135

Author(s):

Maoliang Shen ◽

Xuexi Chen

Keyword(s):

Diffusion Coefficient ◽

Pore Structure ◽

Vibration Frequency ◽

Gas Diffusion ◽

Diffusion Resistance ◽

Diffusion Kinetic ◽

Gas Desorption ◽

Coal Particles ◽

Gas Molecules ◽

And Diffusion

To study the influence of vibration on gas desorption and diffusion in particle coal, gas desorption experiments on soft coal with outburst risk under different frequency vibrations were carried out by using a self-designed gas adsorption and desorption platform under vibration conditions, and the influence of different frequency vibrations on the diffusion kinetic parameters was quantitatively analyzed by using a dynamic diffusion coefficient model. The influence mechanism of vibration on gas desorption and diffusion in coal was further analyzed from the three aspects of gas molecules, energy conversion and pore structure through theoretical analysis and mercury injection experiments. The results showed that with increasing vibration frequency, the gas desorption of the coal samples first increases and then decreases. The initial diffusion coefficient of gas in the coal samples increases linearly with increasing vibration frequency, but the attenuation coefficient of the diffusion coefficient decreases first and then increases with increasing vibration frequency. The "throwing effect" and thermal effect of vibration on the gas molecules are both conducive to the desorption of gas molecules. In addition, vibration causes changes in the pore structure in coal, increasing gas diffusion paths and reducing diffusion resistance.

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Correlation of Pore Structure and Permeability by SEM-Image Analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100180896 ◽

1990 ◽

Vol 48 (1) ◽

pp. 428-429

Author(s):

C. A. Callender ◽

Wm. C. Dawson ◽

J. J. Funk

Keyword(s):

Image Analysis ◽

Pore Structure ◽

Imaging System ◽

Pore Space ◽

Simulation Models ◽

Image Analyzer ◽

Imaging Data ◽

Sem Images ◽

Thin Sections ◽

Rock Types

The geometric structure of pore space in some carbonate rocks can be correlated with petrophysical measurements by quantitatively analyzing binaries generated from SEM images. Reservoirs with similar porosities can have markedly different permeabilities. Image analysis identifies which characteristics of a rock are responsible for the permeability differences. Imaging data can explain unusual fluid flow patterns which, in turn, can improve production simulation models.Analytical SchemeOur sample suite consists of 30 Middle East carbonates having porosities ranging from 21 to 28% and permeabilities from 92 to 2153 md. Engineering tests reveal the lack of a consistent (predictable) relationship between porosity and permeability (Fig. 1). Finely polished thin sections were studied petrographically to determine rock texture. The studied thin sections represent four petrographically distinct carbonate rock types ranging from compacted, poorly-sorted, dolomitized, intraclastic grainstones to well-sorted, foraminiferal,ooid, peloidal grainstones. The samples were analyzed for pore structure by a Tracor Northern 5500 IPP 5B/80 image analyzer and a 80386 microprocessor-based imaging system. Between 30 and 50 SEM-generated backscattered electron images (frames) were collected per thin section. Binaries were created from the gray level that represents the pore space. Calculated values were averaged and the data analyzed to determine which geological pore structure characteristics actually affect permeability.

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