【作者】 张锐；

【导师】 王亮；

【作者基本信息】 中国矿业大学 ， 安全工程（专业学位）， 2019， 硕士

【摘要】 为了防治高瓦斯突出煤层煤巷综掘工作面粉尘造成的职业危害和消除煤尘发生爆炸的危险性,对淮北矿区7个高瓦斯突出矿井不同煤层进行取样测试分析研究;同时,针对许疃煤矿3₂38机巷综掘工作面现场情况,对该工作面粉尘运移规律进行了数值模拟研究;并通过实验分析和模拟结果分析对现场工作面产尘特点进行了客观分析;另外,在3₂38机巷工作面进行的煤层注水和泡沫降尘试验结果表明,单独的煤层注水降尘效果不明显,而泡沫降尘技术较普通外喷雾降尘效率显著提高。论文主要研究内容如下:1)对7个煤矿不同煤层进行突出煤体取样测试分析,采用实验室测定分析的方式分析突出煤体的多元基础特性;同时对各个煤层煤样进行区域突出危险性预测指标考察和测定分析,从突出煤体瓦斯多元特性的角度对不同煤体进行研究;然后再对突出煤体的煤尘润湿特性进行研究;最后,结合多元测试参数的整理结果进行综合分析,结果表明:所取煤样的多元参数与煤尘润湿特性有一定的相关性;2)通过一元线性回归、多元线性回归、主成分分析的方法,分析得出煤尘润湿特性的影响因素相关系数、多元线性回归方程、以及相关程度结果。主要结论有:煤组成成分对煤尘接触角影响的最佳回归方程为θ=120.042-2.218（灰分）,表明煤组成成分中,矿物质含量对煤尘润湿性影响最大;煤的微观结构参数对煤尘接触角影响的最佳回归方程为θ=111.866-18.044（比表面积）,表明煤微观结构参数中,比表面积与煤尘润湿性相关性最好;利用主成分分析法进行相关程度排序,得到各相关因素与接触角的相关程度由大到小依次为:灰分A_d>水分M_ad>孔容>比表面积>坚固性系数f值>羟基（-OH）含量>固定碳F_cad>挥发分V_daf>吸附常数b>煤层最大瓦斯压力P>瓦斯放散初速度?p>吸附常数a>最可几孔径。3)结合3₂38机巷工作面现场布置情况,模拟了煤巷综掘面风筒开始供风的140s内巷道风流分布情况,发现风流场在80s后基本稳定,表明在80s后进行粉尘源的释放比较接近现场掘进释放粉尘的情况;进而模拟了一般情况下现场粉尘运移分布规律,结果表明,在巷道掘进前60s内粉尘快速充满巷道,分析掘进开始第60s时巷道粉尘浓度分布发现,粉尘源的位置浓度最高,并在回风侧也有很高浓度的粉尘分布;局部巷道风流紊乱或者风速较低的进风侧存在高浓度粉尘积聚,巷道顶板和风筒壁面附近很快聚集高浓度粉尘团,此外还有大量的粉尘被巷道壁面捕获,巷道底板同时快速沉积起大量的粉尘;另外,结合现场的不同作业条件,模拟了不同分散度条件下的巷道粉尘运移规律,结果表明,不同分散度条件下第60s的粉尘浓度依旧在回风侧最高,随着粉尘分散度降低,空气中粉尘的逸散能力减弱,空气中存在的整体粉尘浓度降低,底板附着的大颗粒粉尘浓度升高,在MD=50μm条件下掘进开始第60s时大多数粉尘很难到达距离掘进面50m处,即降尘的重点区域出现逐渐向前移动的趋势。4)通过数值模拟的结果分析了现场综掘面应当把防尘重点放在掘进面前50m内的回风侧区域,并定期清理巷道积尘,同时认为应当加强粉尘源处的降尘工作;通过对突出煤层的煤样性质分析发现煤样中的游离二氧化硅含量较高,润湿性较差,对人体危害大,并且降尘难度大。此外,在现场工作面进行单纯的煤层注水降尘试验降尘效果并不理想;而泡沫降尘试验结果表明降尘效果较原有外喷雾降尘效果显著提高。更多还原

【Abstract】 In order to prevent and control occupational hazards caused by dust in fully mechanized driving face of coal roadway in high gas outburst coal seam and eliminate the risk of coal dust explosion,the sampling test and analysis of different coal seams in seven high gas outburst mines in Huaibei mining area were carried out.At the same time,referring to the field situation of 3₂38 machine roadway fully mechanized driving face in Xutuan Coal Mine,the dust migration law of the working face was numerically simulated and studied.The experimental analysis and simulation results analysis objectively analyzed the characteristics of the dust produced on the working face.In addition,the results of coal seam water injection and foam dust falling test on the 3₂38 roadway working face showed that the effect of the single seam water injection was not obvious,and the foam dust reduction technology significantly improved the dust removal efficiency.The main contents of this paper are as follows:1)Sampling test and analysis of outburst coal in seven coal seams,using laboratory measurement and analysis method to analyze the multi-basic characteristics of outburst coal;at the same time,the regional outburst risk prediction index of each coal seam was investigated,measured and analyzed,and different coal bodies were studied from the perspective of multi-characteristics of outburst coal gas;and then the coal dust wettability of outburst coal body was studied.Finally,combining the results of the multivariate test parameters,the comprehensive analysis shows that the multivariate parameters of coal samples have a certain correlation with the wettability characteristics of coal dust.2)Through the methods of single linear regression,multiple linear regression and principal component analysis,the correlation coefficients,multiple linear regression equation and correlation degree results of the influence factors of coal dust wetting characteristics are obtained.The main conclusions are as follows:The optimum regression equation for the influence of coal composition on coal dust contact angle isθ=120.042-2.218（ash）,indicating that the mineral content has the greatest influence on the wettability of coal dust;the optimum regression equation for the influence of coal micro-structure parameters on coal dust contact angle isθ=111.866-18.044（SSA）indicating that the specific surface area is of the greatest relationship among the coal micro-structure parameters.The correlation degree of each correlation factor and contact angle was ranked by principal component analysis,and the order of correlation was Ash A_d>moisture M_ad>pore volume>specific surface area>firmness coefficient f>hydroxyl（-OH）content>fixed carbon F_cad>volatile matter V_daf>adsorption constant b>maximum gas pressure in coal seam P>initial velocity of gas emissionΔp>adsorption constant a>the most probable pore size.3)Combining with the site layout of 3₂38 machine roadway,the distribution of airflow in the roadway within 140 seconds after the start of the air supply from the air cylinder in the fully mechanized face of coal roadway is simulated,and it is found that the airflow field is basically stable after 80 seconds,which indicates that the release of dust source after 80 seconds is close to the situation of the dust release in the field excavation;furthermore,the regularity of the dust transport and distribution in the general situation is simulated,and the results show that the airflow dust fills the roadway rapidly within 60 seconds after excavation.Analyzing the distribution of dust concentration in the roadway at 60s after excavation,it is found that the concentration at the location of dust source is the highest and there is a high dust concentration at the return side.There is a high concentration dust accumulation at the intake side where the local roadway air flow is disordered or the wind speed is low.High concentration dust mass is quickly accumulated near the roadway roof and the wall of the air duct.Dust is quickly captured by the roadway wall,and a large amount of dust is deposited on the roadway floor.In addition,combined with the different working conditions on the site,the law of dust migration under different dispersion conditions is simulated.The results show that the dust concentration of 60s under different dispersion conditions is still the highest on the return side.With the decrease of dust dispersion,the ability of dust escaping in the air decreases.The overall dust concentration decreases,and the dust concentration of large particles attached to the floor increases.When the tunneling starts at 60s under the condition of MD=50um,most of the dust is difficult to reach 50m away from the tunneling face,that is,the key area of dust fall tend to move forward gradually.4)Based on the results of numerical simulation,it is concluded that the dust control in the fully mechanized excavation face should be focused on the return air side within 50 meters of the excavation face,and the dust accumulation in the roadway should be regularly cleaned up.At the same time,it is suggested to strengthen the dust control work at the dust source.The analysis of the coal sample properties in the outburst coal seam shows that the content of free silica in the coal sample is high,the wettability is poor,the harm to human body is worse,and the dust reduction is difficult.In addition,a simple coal seam water injection test is carried out in the field working face and the result is not ideal,while the results of foam dust reduction test showed that the dust removal effect was significantly higher than that of the original spray.更多还原