摘要
利用压汞法、低温氮吸附法、瓦斯等温吸附和解吸试验对平煤八矿构造煤和共生原生结构煤进行综合分析,探讨了构造煤孔隙结构与瓦斯耦合特性。结果表明,构造煤以微孔为主,中孔和大孔相对发育且含较多细颈瓶孔,孔隙连通性差。与共生原生结构煤相比,构造煤各孔径阶段的孔容和孔比表面积都有所增加。构造煤比表面积的增加具有阶段性,即孔径〈1.2 nm时为慢增加阶段,孔径=1.2-4.9nm时为快增加阶段,孔径〉4.9 nm时为稳定阶段。构造煤极限瓦斯吸附量a的增大与比表面积快增加阶段关系密切,但小于其BET比表面积的增幅。瓦斯解吸初期0-2 min内构造煤瓦斯解吸速度和解吸量明显大于共生原生结构煤,与中孔和大孔的变化一致,2 min以后瓦斯解吸迅速衰减。低煤体强度、高瓦斯含量的构造煤以气-煤共溶体形式储集更多弹性潜能,突然卸压时瓦斯膨胀能迅速释放,煤层中发育的构造煤增加了煤与瓦斯突出的危险性。
This article cherishes our wishes to share out our study findings on the coupling characteristics of the pore structure with gas of the deformed coals. For this purpose,we have analyzed the nanometer pore and micron pore of the deformed coal and the symbiontic-nature coal from No. 8 coalmine,Pingdingshan,Henan,by using the mercury intrusion-displacement method and low-temperature liquid nitrogen adsorption experiment. At the same time,we have also implemented the isothermal gas adsorption and desorption experiments in hoping to disclose the relation between the deformed coal and the gas outburst. The results of our experimental investigation demonstrate that the micropores are dominant in the deformed coal. We have also noticed that the pore size and the pore specific surface areas of all the pores are all comparatively bigger than those of the symbiontic-nature coal,which indicates a much greater increase of the macropores and mesopores in the deformed coal. In addition,there can be found that the thin-neckbottle-shaped pores tend to expand further but the pore connectivity decreases in the deformed coal. Meanwhile,the specific surface area tends to increase with the increase of the pore size,which can be divided into three sections： the slow-increase section,in which the aperture is less than 1. 2 nm,the fast increasing section,whose aperture is from 1. 2 nm to 4. 9 nm,and the third section,the smooth section whose aperture is more than 4. 9nm. Our study has found that the increasing trend of a-value（indicating the gas adsorption maximum） of the deformed coal tends to be close to the fast increasing section of the specific surface area,though its slope turns to be less than that of the BET specific surface area. During the short period of 0-2 minutes of the early stage of the gas desorption,the gas desorption velocity and the desorption amount of deformed coal can be found significantly greater than that of the symbiontic-nature coal. Thus,it has proved to be consistent with the variations of the macropores and mesopores.However,two minutes later,the gas desorption would soon be found fading rapidly. In addition,the deformed coals,which reveal the characteristics of low strength,would become the gas-coal con-solution after absorbing the high energy gas with the increase of the elastic potential. And,last of all,we have found that large amounts of macropores and mesopores are in a power to have positive impact on the gas desorption,and the gas expansion energy tends to dissolve rapidly under the action of the external force induced. So the coal and gas outburst tends to happen in the deformed coal areas with the low intensity and high gas content.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2015年第1期123-128,共6页
Journal of Safety and Environment
基金
国家"十二五"科技重大专项(2011ZX05040-005)
河南省高校科技创新团队支持计划项目(14IRTSTHN002)
河南省瓦斯地质与瓦斯治理重点实验室--省部共建国家重点实验室培育基地外部开放基金项目(WS2013A11)
河南省教育厅科学技术重点研究项目(14A440008)
关键词
安全工程
构造煤
孔隙结构
吸附
解吸
煤与瓦斯突出
safety engineering
deformed coal
pore structure
adsorption
desorption
coal and gas outburst
