Study of micro-pores development in lean coal with temperature
- 作者：Yanmei Yu ; Weiguo Liang ; master_lwg@hotmail.com ; Yaoqing Hu ; Qiaorong Meng
- 关键词：Lean coal ; Micro-structure ; High temperature ; Physical reactivity ; Pyrolysis ; Pores development ; Micro-CT
- 刊名：International Journal of Rock Mechanics and Mining Sciences
- 出版年：2012
- 期刊代码：33_13651609
- 类别：civ
- 出版时间：April, 2012
- 卷：51
- 期：Complete
- 页码：91-96
- 文件大小：1634 K
摘要
To investigate micro-pores development of coal under high temperature, experimental studies were performed with fine specimens of lean coal as small as 1 mm in diameter through a new micro-CT system. Through statistical analysis, some fundamental characteristics of pore development are discovered as the temperature increases from 18 to 600 掳C. From 18 to 200 掳C, the porosity of lean coal slightly decreases as a result of dehydration, degassing and thermal expansion of the solid framework. From 200 to 400 掳C, the porosity increases greatly due to a coupling effect of the physical reactivity and pyrolysis. Above 400 掳C, the porosity gradually decreases as a complicated chemical effect of the pyrolysis. Analytic results demonstrate that 70-80%of pores radii of the coal are in the range 0.4-2 渭m. Less than 1%of pores are 20-30 渭m in radius when temperature is lower than 200 掳C. About 0.1%of pores are 30-100 渭m in radius as temperature rising from 300 to 600 掳C. As the temperature rises and approaches a critical temperature of 400 掳C, most of the original regular small pores become connected and gradually grow to irregular and larger pores. Above the critical temperature, the pores become more irregular again while the density of pores increases with the complicated effect of pyrolysis of the coal.