Calculation of gas concentration-dependent diffusion coefficient in coal particles: Influencing mechanism of gas pressure and desorption time on diffusion behavior

Yi, Minghao; Wang, Liang; Cheng, Yuanping; Wang, Chenghao; Hu, Biao

doi:10.1016/j.fuel.2022.123973

Cited by 21 publications

(14 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Domestic and foreign scholars have done a lot of research on the problem of loss compensation in the process of gas content determination (Qi et al, 2007;Liu et al, 2013;Song et al, 2021;Yi et al, 2022). The established empirical/semi- Coal sample irradiation velocity curve (modified from Fu et al, 2008).…”

Section: Determination Of Gas Content In Tectonic Coal Based On Compe...mentioning

confidence: 99%

The characteristics of methane adsorption capacity and behavior of tectonic coal

Zhang

Zhang²,

Zhang³

et al. 2023

Front. Earth Sci.

View full text Add to dashboard Cite

The research of methane adsorption on tectonic coal is an important content to gas disaster prevention and coalbed methane (CBM) exploration in outburst coal seams. Many projects of methane adsorption capacity and behavior of tectonic coal, such as adsorption difference between tectonic coal and its untectonic coal, adsorption evaluation of tectonic coal, factors for adsorption capacity of tectonic coal, gas-solid coupling feature in tectonic coal and supercritical adsorption phenomena of tectonic coal, were carried out by scientists. Combined with a long-term study on organic matter structure and methane adsorption of tectonic coal, the author summarized recent-years’ researches on adsorption capacity and behavior of tectonic coal-methane at home and abroad from the dispute of adsorption ability determination, the thermodynamic characterization of methane adsorption capacity, and the methane adsorption behavior of quantum chemical calculation of the adsorption and the gas content calculation based on loss compensation, respectively. It is believed that the coal structure controls the methane adsorption capacity and behavior characteristics of different tectonic coals, and from the perspective of thermodynamics, the adsorption capacity of different types of coals can be better distinguished. In the future, a more scientific and complete quantum chemical calculation of methane adsorption by tectonic coal and a compensation method based on instantaneous emission loss should be established, so as to better reveal the methane adsorption behavior of tectonic coal and the mechanism of coal and gas outburst. The research has a reference to fine research of coal adsorption and CBM exploration practices.

show abstract

Section: Determination Of Gas Content In Tectonic Coal Based On Compe...mentioning

confidence: 99%

The characteristics of methane adsorption capacity and behavior of tectonic coal

Zhang

Zhang²,

Zhang³

et al. 2023

Front. Earth Sci.

View full text Add to dashboard Cite

show abstract

“…The effects of gas pressure on diffusion coefficient still show different experimental results and interpretations. (1) The diffusion coefficient increases monotonically with the increase of gas pressure. − (2) The diffusion coefficient decreases monotonically with the gas pressure increasing. − (3) The diffusion coefficient decreases and then increases as the gas pressure increases. − (4) The diffusion coefficient fluctuates irregularly with increasing gas pressure. − It is noted that a particle coal was used to measure the diffusion coefficient in most of the diffusion experiments. The basic assumption is that particle coal can be approximated as a coal matrix, in which the gas flow belongs to diffusion driven by concentration.…”

Section: Introductionmentioning

confidence: 99%

Influence Mechanism of Gas Pressure on Multiscale Dynamic Apparent Diffusion-Permeability of Coalbed Methane

Li,

Wang,

et al. 2023

ACS Omega

View full text Add to dashboard Cite

The permeability and diffusion coefficient of coal show multiscale characteristics due to the influence of multiscale pore sizes. The gas pressure will continuously decrease during the coalbed methane (CBM) extraction. However, there are contradictory perceptions in the effect of gas pressure on the diffusion coefficient and permeability. Therefore, it is essential to clarify the influence mechanism of gas pressure on multiscale diffusion-seepage. Diffusion-seepage experiments are carried out using particle coal and cylindrical coal without stress loading. Meanwhile, seepage experiments measured by the steady-state method are conducted under stress loading. The results show that the apparent diffusion coefficient is dynamically attenuated with time in the experiments of particle and cylindrical coal. A new model of multiscale dynamic apparent diffusion is proposed. The mechanism of gas flow in multiscale pores is elucidated. The multiscale pores determine the attenuation of the diffusivity and permeability of coal. The initial apparent permeability decreases and then increases with the increase of gas pressure, which is caused by the effect of gas pressure stretching and multiscale flow regime. Three patterns of permeability with gas pressure, monotonically increasing, monotonically decreasing, and U-shaped changes, will occur.

show abstract

“…In recent years, with the increase of mining depth and intensity, the growing risk of gas hazards, such as gas explosion and coal and gas outbursts, poses a serious threat to work safety. − In order to effectively eliminate the risk of gas outburst, a variety of hydraulic techniques have been proposed to enhance coal permeability, which include coal seam water injection, hydraulic flushing, hydraulic slitting, and hydraulic fracturing. − Hao et al believed that liquid water can seal up the gas within the coal microporosity, so that the gas emission quantity from the working face can be reduced. Crosdale et al .…”

Section: Introductionmentioning

confidence: 99%

Quantitative Evaluation of the Influence of Injected Water on Methane Desorption Behaviors of Coal in the Ordos Basin

Zou,

Liu,

Nie

et al. 2023

Energy Fuels

View full text Add to dashboard Cite

Hydraulic fracturing technology is widely utilized to enhance gas drainage efficiency in underground coal mines. Water plays a crucial role in gas migration within coal after water is injected into the coal seams. In this study, methane desorption behaviors of coal were quantitatively evaluated under the influence of the injected water content. X-ray photoelectron spectroscopy (XPS), mercury intrusion porosimetry (MIP), and methane desorption experiments were combined to reveal the influencing mechanism. XPS results show that sample DLT also has the greatest content of the total oxygen-containing groups, which is 99.67% and 176.55% higher than those of samples HJH and BJG, respectively. MIP results indicate that sample DLT has the smallest pore volume (0.0315 cm3/g) and pore surface area (2.79 m2/g), while sample BJG shows the largest pore parameters. It is confirmed that the pore structures of anthracite are more complex than those of bituminous coals. Methane desorption characteristics of anthracite and bituminous coal are affected by injected water to varying degrees. Gas desorption in bituminous B is the most sensitive to the injected water content, and only 6% of the water content triggers a 46.83% reduction of the methane desorption capacity, which is attributed to the less accessible pore space and more hydrophilic oxygen-containing groups. Due to the highly developed pore networks and less oxygen-containing groups, CH4 molecules are replaced by H2O molecules in anthracite at the lower injected water content (<6%), resulting in the increase of the desorption capacity. The higher water content (>6%) accounts for the pore-blocking effect, resulting in the abrupt reduction of the gas desorption capacity.

show abstract

Calculation of gas concentration-dependent diffusion coefficient in coal particles: Influencing mechanism of gas pressure and desorption time on diffusion behavior

Cited by 21 publications

References 43 publications

The characteristics of methane adsorption capacity and behavior of tectonic coal

The characteristics of methane adsorption capacity and behavior of tectonic coal

Influence Mechanism of Gas Pressure on Multiscale Dynamic Apparent Diffusion-Permeability of Coalbed Methane

Quantitative Evaluation of the Influence of Injected Water on Methane Desorption Behaviors of Coal in the Ordos Basin

Contact Info

Product

Resources

About