为研究褐煤的自然发火特性，采用恒温加热法，对不同尺寸的立方体网状容器内的煤样进行实验，得到煤样的升温曲线和临界自燃点温度。根据实验条件，应用Fluent软件建立煤样升温过程的温度场、空气渗流场和氧气浓度场三场耦合模型。实验与模拟结果表明：煤体体积越大，临界自燃温度越低；当环境温度高于临界自燃温度值，煤体能够自燃，反之煤体不能自燃；煤体升温过程中的温度场、空气渗流场和氧气浓度场是随着时间变化并且相互影响的。
This paper investigates the characteristics of lignite spontaneous combustion, with coal samples piled in cube mesh-boxes of three different sizes, placed in a constant temperature chamber and tested by the isothermal heating method. The temperature-time traces and the critical self-ignition temperature in different size coal piles are obtained. The critical self-ignition temperature is lower for larger stockpile volumes. The heating curves of coal will reach the ignition point when the set ambient air temperature is higher than the critical self-ignition temperature. On the other hand, the coal sample will not be self-ignited. Based on the conditions of the experiment, the temperature field, the air seepage field and the oxygen concentration field are simulated by the Fluent software. The three fields change with time and interact with each other in the entire experiment process.
[1] 李青松. 褐煤化工技术[M]. 北京:化学工业出版社, 2014. Li Qingsong. Lignite chemical processes[M]. Beijing:Chemical Industry Press, 2014.
[2] Sasaki K, Sugai Y. Equivalent oxidation exposure-time for low temperature spontaneous combustion of coal[A]//Ahsan A. Heat Analysis and Thermodynamic Effects. Croatia. InTech, 2011:235-255.
[3] Feng K K. Spontaneous combustion of Canadian coals[J]. CIM Bulletin, 1985, 78(877):71-75.
[4] Smith A C, Miron Y, Lazzara C P. Inhibition of spontaneous combustion of coal[R]. Washington:US Bureau of Mines, 1988.
[5] Kevin B, Nicoloas S, David G. Temperatures of some Turkish coals due to spontaneous combustion[J]. Journal of Mines, Metals & Fuels, 1988, 36(9):434-436.
[6] Gouws M J, Gibbon G J, Wade L, et al. Adiabatic apparatus to establish the spontaneous combustion propensity of coal[J]. Mining Science &Technology, 1991,13(3):417-422.
[7] Clemens A H, Matheson T W, Rogers D E. DTA studies of the low temperature oxidation of low rank coals[J]. Fuel, 1990, 69(90):255-256.
[8] 葛岭梅, 徐精彩. 煤炭低温自燃实验[J]. 陕西煤炭技术, 1989(4):17-20. Ge Lingmei, Xu Jingcai. Experiment of spontaneous combustion of coal at low temperature[J]. Shaanxi Coal Technology, 1989(4):17-20.
[9] 陆伟, 王德明, 周福宝, 等. 绝热氧化法研究煤的自燃特性[J]. 中国矿业大学学报, 2005, 34(2):213-217. Lu Wei, Wang Deming, Zhou Fubao, et al. Study on spontaneous combustion of coal by adiabatic oxidation[J]. Journal of China University of Mining & Technology, 2005, 34(2):213-217.
[10] 刘剑, 王继仁, 孙宝铮. 煤的活化能理论研究[J]. 煤炭学报, 1999, 24(3):317-320. Liu Jian, Wang Jiren, Sun Baozheng. A study on the theory of activation energy of coal[J]. Journal of China Coal Society, 1999, 24(3):317-320.
[11] 张瑞新, 谢和平, 谢之康. 露天煤体自然发火的试验研究[J]. 中国矿业大学学报, 2000, 29(3):235-238. Zhang Ruixin, Xie Heping, Xie Zhikang. Experimental study on spontaneous combustion of ground coal[J]. Journal of China University of Mining & Technology, 2000, 29(3):235-238
[12] Wang Yongjun, Sasaki K, Sugai Y. Measurement of critical self-ignition temperatures of low rank coal piles[C]//Proceedings of the 2014 Coal Operators' Conference. New South Wales, Australia:The University of Wollongong Printery, 2014:339-343.
[13] 王福军. 计算流体动力学分析——CFD软件原理与应用[M]. 3版. 北京:清华大学出版社, 2004. Wang Fujun. Analysis of hydrokinetics:Theory and application of software[M]. 3rd ed. Beijing:Tsinghua University Press, 2004.
[14] 俞昌铭. 多孔材料传热传质及数值分析[M]. 北京:清华大学出版社, 2011. Yu Changming. Numerical analysis of heat and mass transfer for porous materials[M]. Beijing:Tsinghua University Press, 2011.
