基于低温氮吸附法和压汞法的煤样孔隙研究

Study on Porosity of Coal Samples Based on Low Temperature Nitrogen Adsorption Method and Mercury Porosimetry

为了研究无烟煤的孔隙结构特征,采用压汞法和低温氮吸附法对寺河矿煤样进行孔隙特征研究,结果表明该煤样的低温氮吸附等温线接近Ⅰ型,煤中的微孔尤其是小于2 nm的孔构成煤层瓦斯的吸附空间;压汞曲线没有滞后环,多分布圆柱形孔和Ⅴ形孔,大孔、可见孔和裂隙比较发育,构成煤的渗透容积,有利于瓦斯流动,从而有利于瓦斯抽采。低温氮吸附法测试煤的比表面积比较优越,而压汞法测试煤的孔体积分布比较准确,因此将2种方法结合使用,可以更全面地分析无烟煤的孔隙结构。

In order to study the porosity structure features of anthracite, the mercury porosimetry and the low temperature nitrogen adsorp- tion method was applied to study the porosity features of the coal samples from Sihe Mine. The results showed that the low temperature ni- trogen adsorption isotherm of the coal sample was close to type I and the micropore in the coal, specially less than 2 nm would be the ad- sorption spaces of the coal gas. There was no hysteresis loop in the mercury porosimetry curve and there were many column porosity and V porosity distributed. The large porosity, visible porosity and crack were well developed and made up the permeable volume of coal which would be favorable to the gas flow and to the gas drainage. The low temperature nitrogen adsorption method could have more advantages to test the specific surface area of the coal. The mercury porosimetry would be more accurate to test the porosity volume distribution of the coal. Therefore the combined application of both methods, the porosity structure of the anthracite could be fully analyzed.