摘要
We investigated the role of volatiles in the porous structure of coal samples and the corresponding structural deformations that affect the coals＇ methane adsorption capacity. For this study, the volatiles in coal were gradually removed by extraction. Changes in the crystal, textural, and porous structures were identified by means of thermogravimetric analysis, X-ray diffraction, and N2 adsorption/desorption. Changes in the methane adsorption behavior before and after volatile removal were investigated. It was found that changes in methane adsorption could be attributed to volatile-related deformations in the coal＇s porous structure. Microstructural characterizations indicated that the volatiles could be found in two states within the coal, either trapped in the pores, or cross-linked in the network. The former played an important role in constructing the pore spaces and walls within the coal and affected the accessibility of gases. The latter cross-linked state retained the volatiles within the macromolecular coal structural network. This state affected coal-coal interactions, which was a factor that controlled the crystal structure of coal and contributed to the number of porous deformations.
研究了煤中的挥发性物质对煤结构变形的作用,考察了此类结构变形对煤吸附甲烷的影响.实验过程采用溶剂抽提方式逐步移除了煤的挥发性物质.使用热重分析、X射线衍射及N2吸附/脱附等技术方法,考察了抽提前后样品的晶体结构、织构结构以及样品对甲烷吸附能力的差异.结果表明,移除挥发性物质导致煤结构变形,并导致煤吸附甲烷量的改变.微观结构表征证明,挥发性物质以两种形态存在于煤结构中:即其镶嵌在孔道中,或者以交联的方式附着在煤大分子网络中.其中,镶嵌在孔道中的挥发性物质是构筑煤孔道结构重要组成部分,因此影响气体在孔中的储存量;交联在煤大分子网络中的挥发性物质,影响煤与煤之间的分子相互作用,是煤晶体结构的重要参数,其可影响煤的孔结构变形程度.
基金
supported by the National Basic Research Program of China (2011CB201202)
