Influence of Fractal Pores on the Oxidation Behavior of Brown Coal

McMahon, P. J.; Snook, Ian K.; Moss, Susan; Johnston, Peter R.

doi:10.1021/ef980215i

Cited by 21 publications

(6 citation statements)

References 8 publications

(34 reference statements)

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“…The pores and fractures can be divided into two parts: adsorption space (pore size ≤ 100 nm) and seepage space (pore size > 100 nm) (composed of seepage pores and microfractures) . The fractal dimension of the PSD of coal reservoirs is usually between 2 and 3 . As the fractal dimension is close to 3, the pore size distribution is discrete, and the heterogeneity of the reservoir pore is greater.…”

Section: Resultsmentioning

confidence: 99%

Compressibility of Different Pore and Fracture Structures and Its Relationship with Heterogeneity and Minerals in Low-Rank Coal Reservoirs: An Experimental Study Based on Nuclear Magnetic Resonance and Micro-CT

Cheng

2020

Energy Fuels

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Accurate characterization of the compressibility of pores and fractures in coal reservoirs is of great significance for predicting permeability and for optimizing the production of coalbed methane (CBM). However, for low-rank coal (R o,max < 0.65%), compressibility and the influences of different pore structures and minerals on compressibility have not been studied thoroughly. To solve this problem, four low-rank coal samples were collected from the south of Junggar Basin. Low-field nuclear magnetic resonance is used to study the compressibility of pore and fracture in low-rank coal and its relationship with the heterogeneity. In addition, the effects of fracture structure and minerals on compressibility were studied by combining with micro-CT. The results show that the effects on the compression space of the low-rank coal with the increase in effective stress mainly come from the fracture and seepage pore volume, and the compressibility becomes weaker. The low-rank coal reservoirs with well-developed fractures and seepage pores show better compressibility. The compressibility of the pores and fractures in low-rank coal is noticeably affected by the mineral content, mineral shape, and mineral arrangement. When the fracture development is similar, the coal reservoirs with a high mineral content and with many fractures filled by minerals show poor compressibility. There is a negative linear correlation of the compressibility of pores and fractures with the fractal dimension of the seepage space in low-rank coal. Moreover, the closing rate of the pores and microfractures in low-rank coal with significant heterogeneity in the seepage space is faster under confining pressure. The research results are beneficial to the optimization of CBM production measures in low-rank coal reservoirs.

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Section: Resultsmentioning

confidence: 99%

Compressibility of Different Pore and Fracture Structures and Its Relationship with Heterogeneity and Minerals in Low-Rank Coal Reservoirs: An Experimental Study Based on Nuclear Magnetic Resonance and Micro-CT

Cheng

2020

Energy Fuels

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“…Full details of the upgrading procedures used and results with the Victorian Loy Yang brown coals have been reported elsewhere (4,5,(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39).…”

Section: Upgrading Brown Coalmentioning

confidence: 99%

“…Previously we reported an investigation of the effect of these coal treatment processes upon the pore structure of brown coal using SAXS (4,5). Unfortunately this small-angle technique is limited to examination of the coal micro porosity.…”

Section: Upgrading Brown Coalmentioning

confidence: 99%

The Pore Structure in Processed Victorian Brown Coal

McMahon¹,

Snook²,

Treimer³

2002

Journal of Colloid and Interface Science

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“…For all three coals, the pore volumes decreased with increased MTE pressure and the reverse trend was seen with increased MTE temperature. Johnston et al [16] and McMahon et al [17,18] investigated the change in the pore structure of Victorian lignite when upgraded with heated gases. The results they obtained using ultra-small-angle neutron scattering and small-angle X-ray scattering showed that pore collapse would take place when Victorian lignite samples were upgraded by heat treatment using reactive gases at 350 C. In summary, drying with any method will change the physical properties and pore structure of lignite, which may further affect its combustion behavior.…”

Section: Introductionmentioning

confidence: 99%

Combustion and Pollutant Emission Characteristics of Lignite Dried by Low Temperature Air

et al. 2014

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Lignite is a kind of coal that has high moisture content and needs to be dried before being utilized. In this article, a Chinese lignite was dried in air at 120-180 C and the changes in its physical and chemical structures after drying were investigated. The results showed that the pore volume and specific surface area of the lignite decreased after drying. Some of the methylene and methyl groups were oxidized by the oxygen in the drying air, resulting in an increase in oxygen functional groups. The combustion characteristics of the dried coals and parent coal (dry basis) were studied via thermogravimetric analysis. The total volatile yields of the dried coals increased compared to the parent coal. The burnout temperatures of the dried coals were higher than the parent coal, whereas the ignition temperatures stayed almost unchanged. An entrained flow system was set up to study the release of nitrogenous gas products during rapid pyrolysis and combustion. The HCN yields of the dried coals during pyrolysis were higher than that of the parent coal, and a similar trend was found for the NO yield during combustion. The mechanism changes of combustion and pollutant emission characteristics were discussed according to the results of the physical and chemical structure analyses.

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Influence of Fractal Pores on the Oxidation Behavior of Brown Coal

Cited by 21 publications

References 8 publications

Compressibility of Different Pore and Fracture Structures and Its Relationship with Heterogeneity and Minerals in Low-Rank Coal Reservoirs: An Experimental Study Based on Nuclear Magnetic Resonance and Micro-CT

Compressibility of Different Pore and Fracture Structures and Its Relationship with Heterogeneity and Minerals in Low-Rank Coal Reservoirs: An Experimental Study Based on Nuclear Magnetic Resonance and Micro-CT

The Pore Structure in Processed Victorian Brown Coal

Combustion and Pollutant Emission Characteristics of Lignite Dried by Low Temperature Air

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