摘要
研究煤微观结构与其吸附瓦斯特性对瓦斯抽采和灾害防治具有重要意义.该文首先利用扫描电镜和能谱仪实验设备对煤样的微观形貌和元素分布进行了观测,之后用高温高压吸附仪开展了不同压力的煤粒等温瓦斯吸附实验,分析了煤样瓦斯吸附量随时间的变化特性,并对瓦斯吸附/解吸经验公式进行了验证.实验结果发现:煤样表面存在大量孔隙、煤基质以及矿物质;煤样不同位置的元素分布各异,大都以碳氧元素为主;不同压力下瓦斯吸附量随时间先快速增加后缓慢增加直至趋于稳定,稳定条件下的瓦斯吸附量与压力成线性增加关系;实验数据与经验公式的拟合效果较好,侧面证明了经验公式的正确性,其中常数A和B与吸附压力成正比.学生对该实验的满意度在95%以上.
Abstract
[Objective]There are many associated energy sources in the coal mining process,and gas is one of them.However,gas explosion accidents have always been one of the most influential accidents in coal mining,which seriously hinders safe and efficient underground mining.Coal is a porous medium with many pores and fissures,and these microscopic pores and fissures will affect its adsorption and desorption properties of gas.Therefore,it is of great significance to study the microstructure of coal and its adsorption properties for gas extraction and disaster prevention.[Methods]Based on this,the obtained coal samples were first broken and screened,and then the microscopic structures of coal samples with magnification scales of 30,10,2 μm and 500 nm were investigated by scanning electron microscopy.The element distribution law was obtained by surface scanning of the microscopic morphology images of coal samples at the 100 μm scale using an energy spectrometer.Then,the isothermal gas adsorption experiment of coal particles under different pressures was conducted using a high-temperature and high-pressure adsorption instrument.The change characteristics of the gas adsorption amount of coal samples over time were analyzed and verified with the empirical formula of gas adsorption/desorption.Finally,the application of the experiment content in the experimental teaching reform was discussed.[Results]The results show that there are a lot of pores,coal matrix,and minerals on the surface of the coal sample,and the observed phenomena are different under different magnification scales.The shape of the pores is round at 500 nm,the pore size is approximately 500 nm,and a lot of debris is attached to the surface.The overall element distribution of the coal sample is dominated by C and O,and its weight percentage and atomic percentage can reach more than 90%.However,the element distribution is different at different locations,and there are a lot of Al,Si,and other elements in some locations,which suggests that some minerals may be contained in this location.Under different pressures,the gas adsorption capacity increases rapidly at first and then slowly until it becomes stable.Under stable conditions,the gas limit adsorption capacity and adsorption pressure increase linearly.The experimental data fit well with a Langmuir-type empirical formula with the NTH power of t,and the correlation coefficients are all above 0.99,proving the correctness of the empirical formula.The constants A and B are proportional to the adsorption pressure,representing that the gas adsorption amount and gas adsorption rate under the limit time are proportional to the adsorption pressure.[Conclusions]By guiding students to understand the internal microstructure of coal and characterizing it,students'hands-on ability is exercised,and their understanding of the properties of coal porous media is deepened.Integrating experimental content into experimental teaching can significantly increase students'interest.The test of student satisfaction shows that students'satisfaction is above 95%,which greatly improves the experimental teaching results.This method is significant in enriching the content of students'experimental courses and reforming the experimental teaching system.
基金项目
山东省本科教学改革研究项目(Z2023073)
山东省研究生教育教学改革研究项目(SDYJSJGC2023023)
山东省高等学校青年创新科技支撑计划(2023KJ305)
山东科技大学优秀教学团队培育计划(TD20231203)
山东科技大学青年教师教学拔尖人才培养计划(BJ20211113)
山东科技大学教育教学研究"群星计划"项目(QX2022ZD01)
NETL
NSTL
万方数据