Temperature field distribution of burnt surrounding rock in UCG stope

• Published in: International journal of mining science and technology Vol. 24; no. 4; pp. 573 - 580
• Main Authors: Xin, Lin, Wang, Zuotang, Huang, Wengang, Kang, Guojun, Lu, Xuefeng, Zhang, Peng, Wang, Jianhua
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2014; Low Carbon Energy Institute, China University of Mining & Technology, Xuzhou 221116, China%Xuzhou Coal Mining Group, Xuzhou 221006, China; State Key Laboratory of Coal Resources and Safe Mining, China University of Mining & Technology, Xuzhou 221116, China; School of Mines, China University of Mining & Technology, Xuzhou 221116, China; Key Laboratory of Deep Coal Resource Mining, Ministry of Education of China, Xuzhou 221116, China%State Key Laboratory of Coal Resources and Safe Mining, China University of Mining & Technology, Xuzhou 221116, China; Elsevier
• Subjects: Burnt surrounding rock; Coking cycle; Envelope curve; Laplace transform; Temperature distribution; UCG; Underground coal gasification (UCG); 一维非稳态导热; 二维非稳态导热; 围岩; 拉普拉斯变换; 温度场分布; 煤炭地下气化; 采场; Temperature distribution; Envelope curve; Burnt surrounding rock; Underground coal gasification (UCG); Laplace transform; Coking cycle
• ISSN: 2095-2686
• DOI: 10.1016/j.ijmst.2014.06.001

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 analyt- ical 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.