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Tongshan, China

Xin L.,China University of Mining and Technology | Xin L.,Key Laboratory of Deep Coal Resource Mining | Wang Z.,China University of Mining and Technology | Wang Z.,Key Laboratory of Deep Coal Resource Mining | And 8 more authors.
International Journal of Mining Science and Technology | Year: 2014

In order to study temperature field distribution in burnt surrounding rock and to determine ranges of burnt surrounding rock, coal-wall coking cycle and heat influence in the underground coal gasification (UCG) stope, based on the Laplace transform and inversion formula, we studied the temperature analytical solution of one-dimensional unsteady heat conduction for multi-layer overlying strata under the first and the forth kinds of boundary conditions, and we also carried out a numerical simulation of two-dimensional unsteady heat conduction by the COMSOL multiphysics. The results show that when the boundary temperature of surrounding rock has a linear decrease because of a directional movement of heat source in the UCG flame working face, the temperature in surrounding rock increases first and then decreases with time, the peak of temperature curve decreases gradually and its position moves inside surrounding rock from the boundary. In the surrounding rock of UCG stope, there is an envelope curve of temperature curve clusters. We analyzed the influence of thermophysical parameters on envelope curves and put forward to take envelope curve as the calculation basis for ranges of burnt surrounding rock, coal-wall coking cycle and heat influence. Finally, the concrete numerical values are given by determining those judgement standards and temperature thresholds, which basically tally with the field geophysical prospecting results. © 2014 Published by Elsevier B.V. on behalf of China University of Mining and Technology. Source


Duan T.,China University of Mining and Technology | Duan T.,Key Laboratory of Deep Coal Resource Mining | Wang Z.,China University of Mining and Technology | Wang Z.,Key Laboratory of Deep Coal Resource Mining | And 10 more authors.
Energy Education Science and Technology Part A: Energy Science and Research | Year: 2012

Integrated calculation method and calculation method of actual measurement method were merely applied for calculating air gas or gas producing with two-stage method and not suit for simulating gasification processes of air-steam method, oxygen-enriched air steam and pure oxygen steam method. Papers of how calculation method of reaction equilibrium been employed in underground coal gasification (UCG) has not been found. In order to guide the design of UCG, the reaction equilibrium model was established to simulate air-steam continuous method, oxygen-enriched air steam continuous method and pure oxygen steam continuous method of UCG. Meanwhile, corresponding three matlab programs was programmed. And it is proven that simulation results coincide with the actual field test data to a great extent. Besides, the rule of simulated UCG index changing along with steam-oxygen ratio is in accordance with lab test results. These show that thermodynamic and chemical processes of UCG can be well simulated by the model and programs. © Sila Science. Source


Duan T.,China University of Mining and Technology | Duan T.,Key Laboratory of Deep Coal Resource Mining | Wang Z.,China University of Mining and Technology | Wang Z.,Key Laboratory of Deep Coal Resource Mining | And 13 more authors.
Energy Education Science and Technology Part A: Energy Science and Research | Year: 2012

Enhancement of efficiency of UCG (underground coal gasification) means reduction of CO2 Emission and improvement of environment. With the practical experience in the UCG power generation field trial in Huating Coal Group of China, six ways of enhancement of efficiency of UCG are put forward which include selecting proper gasification agent flow rate, proper steam and O2 concentration in gasification agent, appropriate oxygen making process and controlling the length of the reduction zone. The enhancement of efficiency of UCG is systemic engineering. All of the ways can be adopted under the conditions of the existing technologies. © Sila Science. All rights reserved. Source


Jin-Long J.,China University of Mining and Technology | Li-Wen C.,China University of Mining and Technology | Hong-Wei L.,Xuzhou Coal Mining Group | Hai-Yang C.,Xuzhou Coal Mining Group | Chang-Sheng Z.,Xuzhou Coal Mining Group
Electronic Journal of Geotechnical Engineering | Year: 2014

Aiming at the poor stability of large section soft and broken roof of coal roadway, we apply limit equilibrium theory as basis for supporting design. Combing theoretical analysis and field measurement determine the limit equilibrium zone of surrounding rock in coal roadway with large section. Based on the scope of limit equilibrium zone, anchor bolt and anchor cable parameters in supporting system are designed to control the stability of surrounding rock. Monitoring the roadway surrounding rock deformation during roadway drivage and working face mining period, and analyses the deformation law. The results show that surrounding rock deformation remain stable from drivage face 50m, and maximum deformation is 80mm; The surrounding rock deformation and deformation velocity is bigger in front of working face 30m, the maximum value are 11mm and 25mm/d, respectively, affected by the mining influence. The deformation meets requirements of the stability of surrounding rock. The supporting design method can improve the overall stability effectively, and ensure the safe and efficient mining. © 2014, ejge. Source


Zhang Z.-Z.,China University of Mining and Technology | Gao F.,China University of Mining and Technology | Gao Y.-N.,China University of Mining and Technology | Yan B.,Xuzhou Coal Mining Group
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2010

In order to study the differences of engineering behavior in large section open-off cut in different construction orders, the mining process of two common orders was simulated by using the software ANSYS. The result data through relevant analysis shows that the stress distribution of surrounding rock presents the shape of butterflies, and it expands toward top left corner and top right corner, which is the possible bumping center. 37 points were selected respectively on two sides of the open-off cut and rock roof, and the change law of equivalent stress at those points in different construction orders was obtained. On the basis of this, the bumping risk of two-sides and rock roof was analyzed, showing that the bumping risk is the worst on right hand of open-off cut in project "first-lead-then-larger". Generalized strain energy density was brought forward and defined, and a simple bumping rule used in given engineering was set up based on the relationship between the change of generalized strain energy density and bumping risk in cutting process. Source

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