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Zhang X.-B.,State Key Laboratory Cultivation Base for Gas Geology and Gas Control HPU | Zhang X.-B.,Henan Polytechnic University | Wang W.,State Key Laboratory Cultivation Base for Gas Geology and Gas Control HPU | Wang W.,Henan Polytechnic University | And 5 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2016

Tectonic coal is the product of strong tectonic compression and shear actions, and its crystalline structure perhaps records the tectonic features. In this paper, the microcrystal structure the organic matter evolution of badly twisted tectonic coal and its symbiotic un-tectonic coal were investigated by means of coal structure analytical method (such as XRD, NMR, GC/MS and so on). Combined with the result of coal deformation-metamorphism feature and the power basis of forming tectonic coal, the confined-space oriented growth mechanism of coal microcrystal is tentatively proposed. The main points of the mechanism include: During forming tectonic coal, the system changed from a closed mode into an open one because of fracture structure, microfractures and cleavage in coal seam, then tectonic coal delamination became the confined spaces of coal microcrystal growth; Tectonic stress, gravity and adsorption were the driving forces for coal microcrystal oriented growth; Being confined-space and orientation binding, the growths and arrangements of coal microcrystallines tended to lie low like that of lamellar crystals, in the meanwhile, coal polymers reached the steady state through self-adjusting molecular conformations and chain arrangements. The results are useful for studying the coal structure evolution and physial-chemical mechanism of forming tectonic coal. ©, 2016, China Coal Society. All right reserved.


Yan J.-W.,State Key Laboratory Cultivation Base for Gas Geology and Gas Control HPU | Yan J.-W.,Henan Polytechnic University | Zhang X.-B.,State Key Laboratory Cultivation Base for Gas Geology and Gas Control HPU | Zhang X.-B.,Henan Polytechnic University | And 2 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2013

Overall investigating into the current coal-gas outburst mechanisms at home and abroad, we analyzed the key factors influencing coal-gas outburst from the perspective of gas geology, such as deformed coal, gas and tectonism. Based on those results, the geological control mechanism of coal-gas outburst centering on gas outburst coal is tentatively proposed. It is pointed out the coal-gas outburst being as follows: in the face of coal wall, gas outburst coal with a certain thickness is extended to expansion and failure due to unloading mining, and permeability of coal seam increases; because of abundant coal bed methane (CBM) desorbing fast, a mixture of CBM and coal particles with higher kinetic energy has been formed instantly in front of the coal wall, like an explosives, and it results in avalanche damage of coal body. Taken the "10·20" mining calamity for example, the geological-control case for coal-gas outburst had been analyzed, and revealed the distribution of gas outburst coal based on gas-geological characteristics of coal mines in China's Xinjiang Uighur Autonomous Region.


Huan X.,State Key Laboratory Cultivation Base for Gas Geology and Gas Control HPU | Huan X.,Henan Polytechnic University | Zhang X.-B.,State Key Laboratory Cultivation Base for Gas Geology and Gas Control HPU | Zhang X.-B.,Henan Polytechnic University | And 2 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2015

Since the parameter k has a great arbitrariness in hypothetical saturation-vapor pressure P0 calculation, the adsorption potential theoretical model, which contains the two indexes P0 and adsorbed-phase density ρa, has a low-precision description in the field of coal-methane adsorption. In this paper, a series of adsorption equilibrium experiments of methane on different coals (low-to medium-grade metamorphic tectonic and its intergrowth untectonic coal samples) were separately conducted at a wide temperature range. Adsorption isotherms from the experiment data were applied to respectively calibrate the P0 and ρa of each coal-methane adsorbed system, and then an adsorption characteristic curve of different adsorbed systems has been derived. It is found that P0 via the k value is closely related with the adsorption characteristics curve, and each coal sample has its own "the optimal k value ", such as kP1N=3.2, kP1D=3.4, kP8N=3.1 and kP8D=3.0. Lastly, the coal-methane adsorption isotherms at the temperatures of 243, 283, 303 and 323 K were forecasted base on the adsorption data at 313 K, and it demonstrates that the forecasted results via the P0, which comes from a combination of Amankwah' calculation, and the optimal k value could tally well with actual results. esults. ©, 2015, Meitan Xuebao/Journal of the China Coal Society. All right reserved.

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