Browsing by Author "Zhang, Shuo"
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Item Open Access Influence of coalification on methane diffusion dynamics in middle-high rank coals(Taylor and Francis, 2021-01-11) Jiang, Jingyu; Zhang, Shuo; Longhurst, Philip; Zhao, Ke; Wang, DeyangUnderstanding the effect of coalification on the diffusion of methane in middle-high rank coals (MHRC) is fundamental for optimizing the coalbed methane (CBM) drainage strategies. Safe coal mining relies critically on this approach. Hence, CH4 adsorption/desorption experiments and a new methane diffusion model were used to study methane diffusion behavior in five different metamorphic degree coals from China. The results indicate that, as the vitrinite reflectance (Ro) increase, the Langmuir volume (VL) shows a downward trend at first, then increases. Coalification especially for the third coalification jump (Ro = 1.26%) shows a turning effect on diffusion dynamics of MHRC. The desorption volume and initial diffusion coefficient (D0) both show a slight decreasing, then rapid increasing trend. The D0 of five coals jumps at Ro = 1.26%. VL increases alongside that of the micropores volume. With the decrease of the Raman parameter ID1/IG, the VL, methane desorption volume within 7200 s and D0 all increase. Results show that coalification changes the microporous structure and the macromolecular structure of the coal, which finally affects the diffusion capacity of coal. Coalification has a positive effect for the gas extraction and the development of CBM for the semianthracites.Item Open Access Molecular structure characterization of bituminous coal in Northern China via XRD, Raman and FTIR spectroscopy(Elsevier, 2021-03-22) Jiang, Jingyu; Zhang, Shuo; Longhurst, Phil; Yang, Weihua; Zheng, ShaojieBituminous coal is used widely for a variety of applications despite causing a range of problems within processes. The complexity and heterogeneity of the molecular structure of coal is one of the reasons for problems during use. Investigation into the molecular structure of the bituminous coal is reported from using X-ray diffraction (XRD), Raman spectroscopy, and Fourier Transform infrared (FTIR) spectroscopy experiments on four coal samples from coal mines in Northern China. The average lateral sizes (La), stacking heights (Lc) and interlayer spacing (d002) of the coal samples’ crystallite structures derived from the XRD ranged from 25.78 to 27.93 Å, 17.27 to 25.88 Å and 3.40 to 3.52 Å, respectively; and the G-D1, ID1/IG and La of the samples ranged from 245.06 to 249.63 cm−1, 2.18 to 2.48 and 18.16 to 20.64 Å, respectively. The FTIR spectra reveals that coal samples incorporate oxygen-containing functional groups, aliphatic functional groups, aromatic functional groups and hydroxyl functional groups. Results show these four coal samples contained a low degree of ordered microcrystalline units with a low degree of aromatic conformation. The samples have the largest proportion of oxygenated functional groups, followed by aromatic structures, aliphatic structures and hydroxyl groups. Results from this study could inform the ongoing study of molecular structural characteristics of bituminous coal as well as help our understanding of properties such as wettability and pore structure.