【作者】 刘贞堂；

【导师】 何学秋；

【作者基本信息】 中国矿业大学 ， 安全技术及工程， 2010， 博士

【摘要】 我国是世界上煤炭产量最大的国家,也是受各种灾害威胁最严重的国家,其中,瓦斯(煤尘)爆炸事故的发生,极大地影响了我国煤矿的安全高效生产和煤炭行业的健康发展。针对瓦斯(煤尘)爆炸基础研究薄弱、事故调查缺乏物证分析基础及技术规范等问题,本文利用建立的瓦斯(煤尘)爆炸实验系统,在爆炸球体及水平管道中对不同浓度瓦斯、煤尘进行了系统的爆炸实验;分析了爆炸特征参数(爆炸压力、火焰温度、火焰传播速度)的变化规律;利用高速摄影技术观测分析了瓦斯(煤尘)爆炸火焰的结构特征;运用热力学理论及方法,计算了瓦斯爆炸的温度和压力,并与实验结果进行对比分析;基于瓦斯(煤尘)爆炸的特征参数及气、固体残留物的特征,初步提出了确定爆炸事故性质及爆源点的判据。全文通过研究得到了如下成果:(1)实验研究了密闭容器(20L爆炸球体、水平管道)瓦斯爆炸、瓦斯煤尘爆炸过程中爆炸压力、火焰温度及传播速度等特征参数的变化规律,爆炸过程中各特征参数随反应时间呈先增大至峰值然后减小的趋势。(2)系统研究了瓦斯浓度、煤尘浓度、煤质等对爆炸特征参数的影响并分析各参数之间的关联效应。结果表明在瓦斯爆炸极限内,瓦斯浓度为9.5%时,爆炸强度最大,爆炸压力、火焰传播速度和温度均达到最大值,三者之间存在正相关性;同一瓦斯浓度条件下,瓦斯煤尘爆炸过程中,煤尘浓度为400g/m3,爆炸压力达到最大值。(3)利用高速摄影技术,研究揭示了瓦斯爆炸和瓦斯煤尘爆炸过程中的火焰结构特征。在瓦斯爆炸过程中,存在火焰破裂现象;在瓦斯煤尘爆炸过程中,火焰沿水平管道可划分为暗区(未燃区)、微亮区、黄红色发光区和白色发光区。(4)系统研究并揭示了瓦斯爆炸、瓦斯煤尘爆炸后气、固体成分及其变化规律。瓦斯爆炸后,其主要成分是一氧化碳、二氧化碳、氢气、氧气、氮气和甲烷等,随瓦斯浓度增大,一氧化碳生成量增加,二氧化碳生成量先增加后减小;瓦斯煤尘爆炸后,随着参与爆炸的煤尘量的增多,一氧化碳、氢气、甲烷的生成量逐渐增加,二氧化碳的变化规律与瓦斯爆炸类似;瓦斯煤尘爆炸后,烟煤、无烟煤、褐煤的残留物中挥发分和固定碳明显降低,灰分含量大幅增加。(5)研究了瓦斯(煤尘)爆炸后氢气生成量的变化特征。瓦斯爆炸时,当瓦斯浓度在5%~12%时,生成的氢气量较少,当瓦斯浓度大于12%时,生成的氢气量大幅增加;瓦斯煤尘爆炸时,随煤尘浓度的增加,生成的氢气量明显增大;氢气的存在降低了瓦斯(煤尘)的爆炸下限,可能是引发矿井瓦斯(煤尘)连续爆炸的主要原因,生成氢气的量在其爆炸极限内未发生爆炸,主要是由于爆炸腔体中氧气浓度较低造成的。(6)基于能量守恒原理,运用热力学理论及方法分析了密闭空间的瓦斯爆炸过程,建立了瓦斯爆炸压力及温度的理论计算公式,在考虑热量损失的前提下,计算了不同瓦斯浓度下瓦斯爆炸温度与爆炸压力,计算结果与实验结果基本相符。(7)依据实验得出的瓦斯爆炸、瓦斯煤尘爆炸后的特征参数及气、固体成分特征及变化规律,初步提出了爆炸事故调查时确定爆炸事故性质及爆源点位置的综合判据。论文研究成果为深入研究瓦斯(煤尘)爆炸事故演化过程及瓦斯煤尘爆炸的物证分析技术提供基础理论依据,对于进一步揭示瓦斯(煤尘)爆炸的细观机理、预防瓦斯煤尘爆炸事故发生等具有深远的理论意义和重要的应用价值。更多还原

【Abstract】 China is one of the largest coal production countries in the world, and also is the most seriously affected by various disasters, where the gas (coal dust) explosion often occurring has greatly affected the safe and high effective production and international reputation of coal mines in China. Considering the problems of the basic research of gas (coal dust) explosion is weak and the basic norm of material evidence analysis in accident investigation is few, the characteristic rule of explosion characteristic parameters, including explosion pressure, flame temperature and flame speed, was theoretically analyzed based on the data from the experiments of gas (coal dust) explosion done in the spherical vessel and the horizontal pipe of the gas (coal dust) explosion experimental system established in this paper. The structure of the flame in the gas explosion and gas and coal dust mixture explosion was analyzed by using high speed photography technique.The temperature and pressure of gas explosion were calculated by using thermodynamic theory and method, then the results were comparing analyzed with experimental results. The criterion determined the nature of explosion accident and explosion source were proposed initially based on the characteristic parameters and the characteristics of gas and solid residues. The results are as follows.(1) Experimentally studied on the change laws of the characteristic parameters such as pressure, flame temperature and propagation speed of gas explosion and gas and coal dust explosion in the sealed containers (20L explosion sphere, horizontal pipe).The characteristic parameters in temporal dimension all showed the trend of increasing first and decreasing after the peak value.(2) The affection of gas concentration, dust concentration, coal quality on the characteristic parameters was investigated systematically and the correlation effect of the characteristic parameters was analyzed. The results showed that within the explosion limit of methane, the explosion intensity was the largest and the pressure, flame speed and temperature were all at their maximum when the gas concentration reached 9.5%, and they have positive correlation. Under the condition of the same gas concentration, the explosion pressure reached to the maximum when the coal dust concentration was 400g/m3.(3) The structure of the flame in the gas explosion and gas and coal dust mixture explosion was analyzed by using high speed photography technique. The phenomenon of flame burst would be emerged in the gas explosion. The flame can be divided into dark area (unburned area), micro-bright area, red and yellow emission region and white emission region along the horizontal pipe in the process of the gas and coal dust mixture explosion. (4) Gas and solid components and their change law of the gas explosion and the gas and coal dust mixture explosion were studied. The main components were carbon monoxide, carbon dioxide, hydrogen, oxygen, nitrogen and methane after gas explosion. The greater the gas concentration was, the larger yield of carbon monoxide was, but the amount of carbon dioxide increased first and then decreased. Along with the increasing of the amount of coal dust which participated in explosion, the formation amount of methane, hydrogen, carbon monoxide increased gradually after gas and coal dust explosion. Meanwhile, the change law of carbon dioxide in gas and coal dust mixture explosion was similar to the situation in gas explosion. The industry composition of soft coal, anthracite and lignite which participated in the gas and coal dust explosion were analyzed comparatively. The volatile and fixed carbon of all kinds of coal decreased significantly but ash increased significantly after the explosion.(5) Variation characteristics of hydrogen generation are researched. The generation of hydrogen is rare when the gas concentration range is from 5% to 12% and hydrogen generation is increasing significantly when the gas concentration is more than 12%.Meanwhile, the generation of hydrogen is increasing greatly with coal dust concentration increasing. The exist of hydrogen decreased the lower explosive limits of gas (coal dust) which maybe the main reason lead to continuous explosion in coal mine. The main reason why the generation of hydrogen without danger of explosion within its explosive limit is the concentration of oxygen is lower in blast cavity.(6) The gas explosion process in the confined space is analyzed and the theoretical formula of the gas explosion pressure and temperature is established based on the energy conservation principle and used thermodynamic theory and method. Considering the premise of heat loss, the gas explosion pressure and temperature are calculated under the different gas concentrations. The calculated results are basically in accordance with the experimental results.(7) Based on the characteristic parameters of gas explosion and gas and coal dust explosion and the characteristics and change law of solid composition, the thesis tentatively proposed the synthetic criterion for determining the nature of explosion and location of explosion source in explosion accident investigation.The researches of the thesis are able to provide theoretical basis for further study of gas (dust) explosion evolution and material evidence analytic technique of gas (dust) explosion and have far-reaching theoretical significance and important potential of application for further revealing the microscopic mechanism of gas (dust) explosion and monitoring and forecasting of rock or coal dynamical disasters.更多还原