基于低温氮吸附和压汞法的焦煤孔隙结构研究

    Study on pore structure of coking coal based on low-temperature nitrogen adsorption and mercury intrusion method

    • 摘要: 为了明确平顶山十二矿深部焦煤孔隙结构特征,采用低温氮吸附法和压汞法相结合对其软硬煤进行实验研究,并利用Menger海绵模型对压汞法所测参数进行孔隙结构分形。结果表明:软硬煤低温氮吸附等温线均接近IV型等温线,软硬煤发育较为一致,有较小的滞后回环,微孔、小孔孔隙类型主要是一端封闭的不透气性孔及封闭孔,中孔以上孔隙以开放性透气性孔为主,软煤中还有部分墨水瓶型孔;压汞法测得软煤孔面积为5.058 m2/g,孔体积为0.037 5 cm3/g,硬煤孔面积为4.641 m2/g,孔体积为0.036 8 cm3/g;软硬煤孔径分布较为一致,吸附空间集中在微孔、小孔,较高的微孔比例有利于瓦斯的储存;焦煤煤样孔隙特征呈“两极化”分布,大孔、可见孔和裂隙比较发育,构成煤的渗透容积,有利于平顶山十二矿煤层瓦斯的流动与抽采,但是较少的中孔孔隙比例可能会造成瓦斯产出运移通道不畅;软硬煤渗流孔具有明显的分形特征,吸附孔分形维数普遍高于渗流孔分形维数,说明微小孔孔隙结构更为复杂,不规则性较强。

       

      Abstract: In order to clarify the pore structure characteristics of deep coking coal in Pingdingshan No.12 Coal Mine, low-temperature nitrogen adsorption method and mercury intrusion method were used to conduct experimental research on its soft and hard coal. The pore structure fractal was carried out on the parameters measured by mercury intrusion method using the Menger sponge model. The results show that the low-temperature nitrogen adsorption isotherms of soft and hard coal in Pingdingshan coking coal are close to the IV isotherm, the development of soft and hard coal is relatively consistent, and there is a small hysteresis loop. The types of micropore and small pore are mainly the impermeable pore and closed pore with one end closed, and the pores above the middle pore are mainly open and permeable; the pore area of soft coal measured by mercury intrusion method is 5.058 m2/g, the pore volume is 0.037 5 cm3/g, the pore area of hard coal is 4.641 m2/g, and the pore volume is 0.036 8 cm3/g. The pore size distribution of soft and hard coal is relatively consistent, the adsorption space is concentrated in micropores and small pores, and a higher proportion of micropores is conducive to gas storage; the pore characteristics of coking coal samples show a “polarization” distribution, and the macropores, visible pores and cracks are compared. It is conducive to the flow and drainage of coal seam gas in Pingdingshan No.12 Coal Mine, but a small proportion of mesoporous pores may result in poor gas production and migration channels; soft and hard coal seepage pores have obvious fractal characteristics, the fractal dimension of adsorption pores is generally higher than that of seepage pores, indicating that the pore structure of micro-pores is more complex and irregular.

       

    /

    返回文章
    返回