易破碎焦煤冲击产尘规律及粉尘特性研究

发布时间：2018-04-27 07:06

本文选题：焦煤 + 产尘　；参考：《山东科技大学》2017年硕士论文

【摘要】：鲁西南A矿焦煤在开采过程中易破碎,产尘量大,粒径小,粉尘防治困难。本文首先对易破碎焦煤的物化特性进行了分析。在此基础之上,根据相似原理,制作了易破碎焦煤的相似材料试样,并利用声发射检测技术对其破裂产尘特点进行分析,然后进行了易破碎焦煤的重力落锤实验,测定了易破碎焦煤的产尘粒径分布规律,最后对易破碎焦煤粉尘的细观孔隙结构进行了测定,得出了其孔隙结构特征。根据本文的研究结论,可以为易破碎焦煤粉尘的防治工作提供基本指导。主要研究内容如下:(1)对煤粉(尘)来源进行分析,研究了易破碎焦煤的物化性质,结果表明:受不同构造应力影响的煤(碎裂煤、碎粒煤、碎粉煤),其宏观、微观特性差别较大,同一工作面不同层位煤样的挥发分,固定碳等含量差别较大。(2)进行了不同组合形式的易破碎焦煤相似材料试样单轴压缩条件下的声发射检测试验,对其各自的破裂产尘特点进行了研究。实验结果表明:对于不同组合形式的相似材料试样,宏观裂纹首先出现及碎粒崩出的位置总是位于软煤相似材料和硬煤相似材料的交界处,软煤相似材料的破坏程度较高,产尘量大;轴向、侧向力学加载过程表明,侧向加载,裂隙沿试样的层理方向扩展,尘源核集中;轴向加载,裂隙向四面八方扩展,尘源核分散。(3)进行了易破碎焦煤的产尘能力及重力落锤实验,得出易破碎焦煤的原生煤尘产尘量与易破碎焦煤单轴抗压强度相关。易破碎焦煤细小颗粒粉尘所占比例与落锤能量有关,研究表明易破碎焦煤尘粒主要集中于“能量产尘粒径拐点”附近(6.62～105.25 μm)。现场落尘特征粒度分析规律表明断层及采掘截割工艺影响各采样点的特征粒度符合附近“能量产尘粒径拐点”的观点。(4)利用低温液氮吸附实验对易破碎焦煤粉尘进行孔隙结构测定,对比了不同易破碎焦煤煤尘的孔隙特征。不同易破碎焦煤煤尘由于地质构造的不同、灰分含量的不同、碳含量的不同,其孔径分布不相同,孔的形态也有较大差别;碎粉煤和鳞片煤煤粉受构造应力的影响最大,其孔隙结构的复杂程度最高;碎裂煤及碎粒煤受构造应力的影响程度较小。分形维数的数值与构造煤粉尘的微观孔隙分布的复杂程度呈正相关关系。
[Abstract]:The coking coal of Southwest Shandong A Mine is easy to be broken in the process of mining, the dust production is large, the particle size is small, and the dust prevention is difficult. In this paper, the physical and chemical characteristics of easily broken coking coal are analyzed. On this basis, according to the principle of similarity, the similar material samples of easily broken coking coal are made, and the characteristics of cracking dust production are analyzed by means of acoustic emission detection technology, and then the gravity drop weight test of easily broken coking coal is carried out. The particle size distribution of easily broken coking coal was measured. Finally, the pore structure of coal dust was determined and the pore structure characteristics were obtained. According to the conclusion of this paper, it can provide basic guidance for the prevention and control of easily broken coking coal dust. The main research contents are as follows: (1) the source of pulverized coal (dust) is analyzed, and the physical and chemical properties of easily broken coking coal are studied. The results show that the macroscopic properties of coal (broken coal, granular coal, pulverized coal) affected by different tectonic stresses are macroscopic. The microcosmic characteristics are quite different, and the volatile matter and fixed carbon content of different coal samples in the same working face are different greatly. The acoustic emission testing tests are carried out under the condition of uniaxial compression of the samples of similar materials of easily broken coking coal in different combination forms. The characteristics of their own rupture and dust production are studied. The experimental results show that for the samples of similar materials with different combinations, the positions of the first appearance of macroscopic cracks and the breakout of particles are always located at the junction of the similar materials of soft coal and hard coal, and the failure degree of similar materials of soft coal is higher. The process of axial and lateral mechanical loading shows that the crack propagates along the stratification direction of the specimen, and the dust source core is concentrated, and the axial loading leads to the crack spreading in all directions. The dust-producing ability and gravity drop weight test of easily broken coking coal were carried out. The results showed that the dust-producing amount of primary coal dust was related to uniaxial compressive strength of easily broken coking coal. The proportion of fine particles dust in easily broken coking coal is related to the falling weight energy. The study shows that the dust particles of easily broken coking coal are mainly concentrated near the inflexion point of energy dust size, which is 6.62 渭 m ~ 105.25 渭 m ~ (-1). The characteristic particle size analysis rule of field dust drop shows that the characteristic granularity of each sampling point affected by fault and cutting technology accords with the nearby viewpoint of "energy dust producing particle size inflection point". (4) using low temperature liquid nitrogen adsorption experiment to easily break coke coal dust To determine the pore structure, The pore characteristics of different easily broken coking coal dust are compared. Because of the different geological structure, different ash content, different carbon content, the pore size distribution is different, the pore shape is also different, the pulverized coal and the scale coal powder are most affected by the tectonic stress. The complexity of pore structure is the highest, and that of broken coal and granular coal is less affected by tectonic stress. The fractal dimension is positively correlated with the complexity of micro pore distribution of tectonic coal dust.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD714.4

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