A review of the application of X-ray computed tomography to the study of coal

Mathews, Jonathan P.; Campbell, Q.P.; Xu, Hao; Halleck, P.M.

doi:10.1016/j.fuel.2017.07.079

Cited by 180 publications

(68 citation statements)

References 114 publications

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“…5) At a low heating rate, Lu coal produced gas and lost its weight at a lower temperature, whereas at a high heating rate it lost its weight at a higher temperature. Takanohashi et al investigated the thermoplasticity of blended high-caking Goonyella coal and slightly caking Witbank coal, using a dynamic viscoelastic measurement with various heating rates (3,5,10,30, 50, 80°C/min). The slight increase of heating rate affected the thermoplasticity of coal blends, and the blend containing 70% slightly caking Witbank coal can be used for coke making when the heating rate is increased to 10°C/min.…”

Section: Numerical Investigation Of the Effects Of Gas-release Rate Amentioning

confidence: 99%

Numerical Investigation of the Effects of Gas-release Rate and Viscosity under Various Heating Rates on Swelling Ratio of Coal in the Coke Production Process

Taki

Hayashizaki

Matsui³

2019

ISIJ Int.

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The effect of heating rate on the swelling ratio of coke during heating of coal was investigated using numerical simulations. The mathematical model in our previous study was modified to observe the effect of the heating rate, and the equation for the reaction rate of coal pyrolysis and gas formation was changed to a first-order temperature-dependent equation. The original and viscosity-dependent classical bubble nucleation equations were compared, and the results showed that the swelling ratio in the numerical simulation results reduced with an increase in the mass transfer rate of gas from coal. At low mass transfer rate (1 × 10 − 13 m 3 /s), the dependence of the swelling ratio on the heating rate was not straightforward. The swelling ratio increased in the order of the following heating rates: 10, 30, and 3°C/min. At high mass transfer rate (1 × 10 − 12 m 3 /s), the swelling ratio increased with increasing heating rate. Experimental results of varying the heating rate agreed well with the results of the large mass transfer case. The numerical simulation results indicated two issues-the gas escaping from coal is a key factor affecting the swelling of coal during heating, and the swelling ratio increased with increasing heating rate because of the short gas release time.

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Section: Numerical Investigation Of the Effects Of Gas-release Rate Amentioning

confidence: 99%

Numerical Investigation of the Effects of Gas-release Rate and Viscosity under Various Heating Rates on Swelling Ratio of Coal in the Coke Production Process

Taki

Hayashizaki

Matsui³

2019

ISIJ Int.

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“…Since the introduction of medical computer tomography (CT) in geological sciences, many applications have been worked out in rock component identification and rock structure damage [11]. Mathews et al [12] reviewed the application of X-ray CT for the study of coal. Much of the initial work was to provide visualization of the internal complexity of coal, and then it allowed obtaining characteristics of pore and fracture structure, mineral composition, and deformation under different conditions [13,14].…”

Section: Introductionmentioning

confidence: 99%

Evolution of Micron‐Scale Pore Structure and Connectivity of Lignite during Pyrolysis

Meng

Zhao

Kang

et al. 2020

Advances in Materials Science and Engineering

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Based on the high-precision microcomputed tomography (micro-CT) technology, the evolution of the μm-scale pore structure and connectivity of lignite during pyrolysis from room temperature to 600°C was studied. The results show that the pore connectivity of lignite increases with the increase of temperature, and the change of pore structure can be divided into four stages: the first stage is from room temperature to 100°C, characterized by generation and connection of small-diameter pores. The second stage is 100–200°C, characterized by rapid expansion and interconnection of pores due to the thermal cracking. The third stage is from 200°C to 450°C, characterized by the slow evolution of pore structure for pyrolysis. The fourth stage is from 450°C to 600°C, characterized by pore interconnection for pyrolysis. 200°C is the temperature at which the μm-scale pore structure of lignite changes dramatically. During the whole pyrolysis process from room temperature to 600°C, the pore quantity of lignite is mainly from the pores of a diameter of 0.65–3 μm. At 200°C and above, the pore volume of lignite is mainly from the pores with a diameter larger than 100 μm, but they are few. These research results have important theoretical reference values for the upgrading and pyrolysis of lignite.

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“…However, a wider range of coal ranks will be encountered during the exploration of coal bed methane and carbon geo-sequestration. Therefore, it is necessary to study the petrophysical properties of all ranked coal samples (Zhao et al 2016;Mathews et al 2017;Mostaghimi et al 2017;Zhou et al 2017). The meso-and microporosity, micro-fractures and elastic properties (such as YoungÕs modulus and PoissonÕs ratio) control the bulk and field-scale estimates of porosity, pore connectivity, permeability, sorption capacity, gas migration, wettability and the seismic analysis of fracture/cleat networks (Al-Yaseri et al 2017;Kumari et al 2018;Li et al 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Micro-CT that has been developed recently allows direct imaging of the coal structure in 3D with high resolution (Mathews et al 2017;Zhang et al 2016a;Jing et al 2017a;Iglauer and Lebedev 2018;Lebedev et al 2017a, b). The voxel size is typically 1-10 lm; thus, percolation thresholds can be estimated more precisely than with 2D SEM measurements (Stauffer 1979).…”

Section: Introductionmentioning

confidence: 99%

Nano-mechanical Properties and Pore-Scale Characterization of Different Rank Coals

et al. 2019

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Characterization of coal micro-structure and the associated rock mechanical properties are of key importance for coal seam exploration, coal bed methane development, enhanced coal bed methane production and CO 2 storage in deep coal seams. Considerable knowledge exists about coal chemical properties, but less is known about the nanoscale to the microscale structure of coals and how they change with coal strength across coal ranks. Thus, in this study, 3D X-ray micro-computed tomography (with a voxel size of 3.43 lm) and nanoindentation tests were conducted on coal samples of different ranks from peat to anthracite. The micro-structure of peats showed a well-developed pore system with meso-and micropores. The meso-pores essentially disappear with increasing rank, whereas the micro-pores persist and then increase past the bituminous rank. The micro-fracture system develops past the peat stage and by sub-bituminous ranks and changes into larger and mature fracture systems at higher ranks. The nano-indentation modulus showed the increasing trend from low-to high-rank coal with a perfect linear relationship with vitrinite reflectance and is highly correlated with carbon content as expected.

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A review of the application of X-ray computed tomography to the study of coal

Cited by 180 publications

References 114 publications

Numerical Investigation of the Effects of Gas-release Rate and Viscosity under Various Heating Rates on Swelling Ratio of Coal in the Coke Production Process

Numerical Investigation of the Effects of Gas-release Rate and Viscosity under Various Heating Rates on Swelling Ratio of Coal in the Coke Production Process

Evolution of Micron‐Scale Pore Structure and Connectivity of Lignite during Pyrolysis

Nano-mechanical Properties and Pore-Scale Characterization of Different Rank Coals

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