水浸烟煤低温氧化过程中微观结构变化规律研究

发布时间：2018-05-22 19:41

本文选题：煤自燃 + 水浸烟煤　；参考：《西安科技大学》2016年硕士论文

【摘要】：西部地区作为我国重要的能源战略储备地,煤炭资源储量丰富,但是其中90%左右的煤质为变质程度较低的烟煤,且所开采煤层的自燃倾向性绝大部分为自燃或者易自燃煤层。在其下层工作面开采过程中,通常采用探水和疏水措施来防治采空区积水水害,这样易形成漏风供氧通道,使遗煤长久处于浸水状况,导致煤体发生变化,从而加大采空区浮煤氧化自燃危险性,容易引起采空区内遗煤的自燃。为了掌握水浸烟煤自燃机理,本文以西部典型矿区烟煤煤样为主要研究对象,采用实验研究与理论分析相结合的方法,对原始烟煤煤样与浸水干燥烟煤煤样在低温氧化过程中微观物理结构和化学结构进行综合实验研究,探究水浸烟煤自燃微观机理,对阻化及有效防治技术的研究具有重要的理论指导意义。借助工业分析实验、扫描电镜实验及比表面积测定实验等,分析了煤样的比表面积、总孔容和平均孔径与煤样自身变质程度之间的关系,研究了原始煤样和水浸干燥后煤样的微观表面物理结构,结果表明:水浸干燥后的烟煤其表面的孔隙和裂隙结构增大且数量明显增多,总孔容与比表面积相似较原始烟煤煤样均有减小,平均孔径增大,孔隙和裂隙连通性更好,有利于对氧气的吸附,加大了烟煤的氧化自燃性。通过XRD衍射实验,研究在三种不同实验条件下的原始烟煤和浸水干燥烟煤煤分子中的微观晶体结构特征的变化规律,得出煤的变质程度、不同氧化温度和煤样本身粒度对水浸烟煤芳香微观晶体结构变化的影响规律。采用FTIR红外光谱实验,对原始烟煤及水浸干燥烟煤进行不同变质程度和不同氧化温度的红外光谱特征分析研究,结果表明:煤分子中含量最大官能团的是含氧官能团,其次是脂肪烃和羟基,含量最小的官能团是芳香烃;在低温氧化过程的前期,水浸煤煤分子中的芳香核结构相对比较稳定,基本不参与复合反应,而脂肪烃和含氧官能团的反应活性较强,其中的甲基、亚甲基、羧基、醚键和芳香醚氧键容易与氧发生复合反应,这些基团可能是煤氧复合发生自燃的诱导因素,导致煤样自燃的主要活性基团。
[Abstract]:As an important strategic reserve of energy in China, the western region is rich in coal resources, but about 90% of the coal is bituminous coal with low metamorphism, and the spontaneous combustion tendency of the coal seams is mostly spontaneous combustion or spontaneous combustion. In the mining process of the lower coal face, water exploration and drainage measures are usually used to prevent the water damage in the goaf, which is easy to form the air leakage oxygen supply channel, make the residual coal in the water immersion condition for a long time, and cause the coal body to change. Therefore, the danger of oxidizing spontaneous combustion of floating coal in goaf is increased, and the spontaneous combustion of residual coal in goaf is easy to be caused. In order to understand the spontaneous combustion mechanism of water-immersed bituminous coal, this paper takes the bituminous coal samples of typical mining areas in the west as the main research object, and adopts the method of combining experimental research with theoretical analysis. The microphysical and chemical structures of raw bituminous coal samples and soaking dried bituminous coal samples during low temperature oxidation were studied, and the microscopic mechanism of spontaneous combustion of water-immersed bituminous coal was explored. It has important theoretical guiding significance for the research of blocking and effective prevention and cure technology. The relationship between the specific surface area, total pore volume and average pore size of coal samples and the degree of metamorphism of coal samples was analyzed by means of industrial analysis, scanning electron microscopy and specific surface area measurement. The microscopic surface physical structure of the raw coal sample and the coal sample after water leaching and drying are studied. The results show that the pore and fissure structure of the bituminous coal surface after water leaching and drying is increasing and the number of the bituminous coal surface is increasing obviously. Compared with the original bituminous coal, the total pore volume and specific surface area are similar to those of the original bituminous coal. The average pore size is increased, and the porosity and fracture connectivity are better, which is favorable to the adsorption of oxygen and increases the oxidation spontaneous combustion of bituminous coal. By means of XRD diffraction experiment, the changes of microcrystalline structure characteristics of raw bituminous coal and soaking dried bituminous coal in three different experimental conditions were studied, and the metamorphic degree of coal was obtained. The effect of oxidation temperature and coal particle size on the microstructure of aromatic bituminous coal is studied. The infrared spectrum characteristics of raw bituminous coal and water-immersed dried bituminous coal with different metamorphism and oxidation temperature were studied by FTIR infrared spectrum experiment. The results showed that the largest functional groups in coal molecules were oxygen-containing functional groups. The second is fatty hydrocarbon and hydroxyl group, and the least content is aromatic hydrocarbon. In the early stage of low temperature oxidation, the structure of aromatic nucleus in water-immersed coal is relatively stable and does not take part in the compound reaction. However, the reaction activity of fatty hydrocarbons and oxygen-containing functional groups is strong. Methyl, methylene, carboxyl, ether bond and aromatic ether oxygen bond are easy to react with oxygen. These groups may be the inducing factors of coal and oxygen compound spontaneous combustion. The main active groups leading to spontaneous combustion of coal samples.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD752.2

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