煤岩比表面积表征方法

Characterization Method for Coalbed Specific Surface Area

为准确表征煤岩比表面积,以鄂尔多斯盆地韩城矿区煤岩为例,进行氮气、二氧化碳和甲烷的吸附等温实验,从煤岩甲烷等温吸附测得的兰氏体积和气体吸附法测得的比表面积相关性分析可知：甲烷吸附能力与二氧化碳SD-R呈正相关关系,与氮气SBET相关性不明显。基于煤岩的二氧化碳吸附数据,运用DFT模型计算微孔分布可知,煤含有大量孔径为0.5~1.0 nm的微孔,基于微孔充填理论的二氧化碳SD-R比氮气SBET更能有效地反映煤岩的吸附能力。鉴于煤岩具有微孔较为发育、微孔控制吸附能力的特点,建议在分析煤岩比表面积时采用二氧化碳吸附SD-R进行表征。

Taking Hancheng coal mining area in Ordos basin as an example, this paper presents the isothermal adsorption experiment of N2 and CO2 to make proper characterization of coalbed specific surface area. The correlation analysis between Langmuir volume from coalbed methane isothermal adsorption and specific surface area from NJCO2 gas adsorption indicates a positive correlation between coalbed methane adsorption capacity and CO2 SD-R, and a weak correlation between coalbed methane adsorption capacity and N2 SBET. According to the coalbed CO2 adsorption data, coalbed contains a great number of micropores with diameter of 0.5-1.0 nm by DET model calculation approach, while for N2 adsorption data, it has poor effective mieropores, which shows that CO2 SD-R is more representative of the coalbed adsorption capacity than N2 SBET. SO the coalbed is characterized by more developed micropores and they control adsorption capacity. It is suggested that the coalbed specific surface area should be characterized by C02 SD-R