自燃煤矸石山深部温度场分布规律及热源反演模型研究

发布时间：2018-05-06 15:15

本文选题：自燃 + 煤矸石山　；参考：《中国矿业大学(北京)》2017年博士论文

【摘要】：煤炭开采对国民经济的发展起着不可或缺的重要作用,随着经济的迅猛发展,煤炭需求量日益增加,伴随着煤炭开采过程会产生固体废弃物—煤矸石。露天堆放的煤矸石山极易发生自燃,对土壤、地下水、大气等矿区环境产生污染,甚至频发矸石山坍塌、滑坡、爆炸等事故危害人们的生命财产安全。国内一些自燃煤矸石山的治理实践案例中,常出现治理效果不佳或复燃的现象,究其原因,是对煤矸石山自燃状况不清楚,特别是对深部燃烧的分布特征不清楚,即使配备比较全面、科学的治理措施,也往往会因无法确切了解自燃矸石山的燃烧状况和深部火源分布情况,使得治理措施不到位,导致功亏一篑。因此,对具有自燃倾向的煤矸石山,需要开展深部温度分布规律以及深部热源定位的研究,为掌握煤矸石山深部燃烧状况和热源分布状况提供科学参考。通过掌握的热源分布情况,可以有针对性的对有自燃隐患的煤矸石山进行早期预警和治理,达到彻底控制煤矸石山自燃的目的。本文在借鉴已有成果的基础上,充分利用热物理学、传热传质学、土壤学、测绘学、固体热传导理论等相关知识,开展了野外模拟实验,主要针对煤矸石山内部处于“自我加热”阶段,设计了煤矸石山有源温度场实验,根据大量的实测数据,揭示了深部温度场温度分布规律,讨论了不同深度温度影响区域划分问题,提出深部有源温度场温度分层模型,即表层、交界层、里层;通过对深部温度分布规律的分析,分别探索了热源强度与最大影响范围、最远传播距离的函数关系;在定性与定量分析的基础上,构建“非稳态导热”情况下热源温度与深度的函数关系模型,提出“稳态导热”情况下热源温度和深度反演模型;针对煤矸石山深部高温热源引起表面温度热异常的情况,提出一套基于热红外技术和近景摄影测量技术联合构建表面温度场的理论与方法,有如下认识。(1)以煤矸石山自燃的内部客观条件相似原则为基础,设计了煤矸石山有源温度场野外模拟实验,基于实测的温度数据,揭示了煤矸石山深部水平方向温度分布规律,规律如下:①在不同热源强度条件下,每个水平层,随着时间的推移,热源影响区域范围逐渐增大,影响区域的温度也在逐渐增加,当热源温度稳定一定时间段后,热源的影响区域即受影响区域的温度基本趋于稳定;②竖直方向距热源中心0-0.6m水平层,热源的影响半径约为0.3m,影响半径以内的区域温度升高较明显,影响半径以外的区域温度在15-25℃左右浮动。这说明煤矸石的导热性能较差,在利用温度探头对热源定位时,要合理放置温度探头才能实现对热源位置的精确定位,同时,随着距热源距离的增加,各个水平层温度逐渐降低,热传导在逐渐减弱;③研究发现:位于热源正上方0.1m水平面的测点比位于热源水平面的测点温升幅度更大,温升速度更快,其原因可能是由于矸石山内部温度分布不均匀,形成不均匀的空气密度场,这空气密度场产生浮升力,形成内部空隙间的对流换热,由于内部空隙较小,表现为热弥散效应,引起热量的平均化,强化正上方的传热过程,导致温度较高,因此,竖直方向上的对流及其带来的热弥散效应要强于水平方向;④定量化揭示了热源强度、水平层高度与温升速率三者间的多项式函数关系,根据三者的函数关系反演温升速率,最大误差为0.86,最小误差为0.00;⑤对温度损失率变化规律分析有:温度损失率在深度0-0.2m迅速下降,随着深度的增加0.2-0.6m,温度损失率又逐渐上升,其中在深度0.2m时最低,可以看出水平层为0.2m的热弥散效应最明显、最强烈。(2)揭示了煤矸石山深部竖直方向温度分布规律①针对热源正上方各个测点温度变化分析发现:距热源0-0.6m范围内,温升较大,温度受热源影响较大;距热源0.6-1m范围内,热源对该范围内的温度影响逐渐开始减弱;距热源1-1.5m范围内,温度受热源的影响急剧减弱,外界环境温度开始逐渐影响该区域,特别是在热源放热强度较低的情况下,这反应了煤矸石山内部处于氧化放热初期时,热源较隐蔽,探测难度较大,只能通过合理布设加密测点的位置,实时监控各个测点的温升变化情况来判定是否存在高温热源点;在1.5-1.8m范围内,温度随外界环境温度呈日规律性变化,因此,如果利用浅层或表面测点的温度进行深部温度预测时,需要综合考虑内部、外界各种因素的影响,或避开受外界环境温度影响的深度范围,基于上述研究结果,提出煤矸石山深部有源温度场温度分层模型,由表及里依次分为:表层、交界层、里层,表层指距矸石山表面0-0.3m范围,该区域受外界环境温度影响较大;②根据对比热源正上方以及距热源0.2m两条竖直轴线上各个测点的温度分布规律发现:在竖直方向上距热源0.2m处的热弥散效应最明显;距热源0.2m竖直轴线上的测点温度比热源正上方的测点温度低两倍左右,因此,在利用注浆灭火法对自燃火源治理时,要提前采用科学、合理的技术手段进行深部火源位置预判,通过竖直方向向下打孔才能有效的对火源温度进行探测以及对火源位置的精确定位;③分析温度损失率变化规律可得:煤矸石山内部处于“自我加热”阶段时,点热源的热量不易向外扩散,需要点热源的热量进行大量的聚集、积累,点连成片,形成区域,当该区域集聚的温度达到燃点时,引发自燃,因此,可以推断在煤矸石山内部最先引发自燃的应该是一个小区域,而不仅仅是一个点。(3)定量分析热源强度与最大影响范围、最远传播距离的关系研究发现:热源强度分别与最大影响范围、最远传播距离呈幂函数关系:f(x)=-296.7x-1.072+2.089, fO) = 2.05*10-6x2.274+0.6506,根据定量化关系可预测不同热源强度下的最大影响范围以及最远传播距离,为后续火源的探测和定位奠定基础。(4)构建深部温度场反演模型①针对矸石山内部处于“非稳态导热”情况下,提出热源温度与深度的函数关系模型:T = a·eb(x-d) + c,该模型能够有效的预测矸石山深部潜在热源点的最小深度以及预测不同深度处的热源温度;②针对矸石山内部处于“稳态导热”情况下,基于热传导理论,提出热源深度反演模型,研究表明:热源深度模型反演的深度最大误差为0.087m,最小误差为 0.06m;③针对矸石山内部处于“稳态导热”情况下,提出热源温度反演模型,将热源温度反演分为三个步骤,先利用热源深度反演模型反演深度,再利用地表能量热平衡方程反演上交界层温度Td,再将深度及上交界层的温度作为初始值,基于提出的热源温度与深度指数增长关系函数T=Td·b.a·(Rd)+c,反演热源温度,最后利用实测的温度数据验证模型可靠性和精度,研究发现:模型反演的最大误差为6.82℃,最大相对误差为2.62%。(5)提出自燃煤矸石山表面温度场构建的原理与方法①对表层温度分布分析发现:煤矸石山表面温度受环境温度和太阳辐射的影响呈现周期性的变化规律,随着距矸石山表面距离的增加,温度受外界环境温度的影响减弱。本研究针对深部热源温度引起表面热异常的煤矸石山情况,基于热红外技术与近景摄影测量技术,提出一套两者联合构建煤矸石山表面温度场的原理与方法,通过定位表面热异常区域对深部燃烧情况作出合理的预判和解译,再结合深部温度场反演模型对热源分布状况和位置进行定位,研究表明:构建的表面温度场的空间坐标最大点位中误差为0.014m,最小点位中误差为0.005m;②提出基于表面温度推演深部温度的概念模型:首先根据构建的煤矸石山表面温度场判定热异常区域,再利用地表能量热平衡方程通过表面温度反演上交界层温度,最后利用深部温度场反演模型反演热源温度和深度,能够有效的定位热源,掌握深部热源燃烧情况。煤矸石山自燃的治理是一项长期且艰巨的任务,尤其是对深部燃烧情况的掌握以及火源定位技术是极为重要的,本研究为探索煤矸石山深部温度分布规律提供一个探索性的认识,同时为构建深部温度场反演模型奠定基础,由于煤矸石山内部燃烧情况极其复杂以及受实验条件的制约,很多认识和探索具有一定的局限性,未来应对不同的热源燃烧状态以及不同的分布位置进行深入研究,为自燃煤矸石山火源定位技术提供更多的科学参考,实现矿区生态环境的绿色发展。
[Abstract]:Coal mining plays an indispensable and important role in the development of the national economy. With the rapid development of the economy, the demand for coal is increasing. Along with the coal mining process, solid waste - coal gangue will be produced. The coal gangue mountains in the open pit are prone to spontaneous combustion, causing pollution to the soil, groundwater, air and other mining areas, and even frequency. The collapse of Gangue Mountain, landslide, explosion and other accidents endanger people's life and property safety. In some domestic practice cases of spontaneous combustion of coal gangue mountains, there is often a phenomenon of poor treatment effect or reignition. The reason is that the spontaneous combustion of Coal Gangue Mountain is not clear, especially the distribution characteristics of deep burning are not clear, even if it is equipped with a relatively complete set. On the other hand, the scientific control measures will often result in the inability to understand the burning status of the spontaneous combustion gangue and the distribution of the deep fire source, and make the treatment unsuccessful and lead to failure. Therefore, for the coal gangue mountains with spontaneous combustion tendency, the study of the deep temperature distribution rules and the deep location of the heat source should be carried out to grasp the Coal Gangue Mountain. In order to control the spontaneous combustion of coal gangue mountains, this paper makes full use of thermal physics and heat and mass transfer on the basis of the existing results. In the field of "self heating" in the Coal Gangue Mountain, the experiment of the active temperature field of Coal Gangue Mountain is designed mainly in the "self heating" stage. According to a large number of measured data, the temperature distribution in the deep temperature field is revealed, and the influence of different depth temperature is discussed. The temperature stratification model of deep active temperature field, the surface layer, the boundary layer and the inner layer, is proposed. By analyzing the distribution of the deep temperature, the function relation of the heat source strength and the maximum influence range and the farthest propagation distance is explored respectively. On the basis of the qualitative and quantitative analysis, the heat source under the condition of "unsteady heat conduction" is constructed. The temperature and depth inversion model of the heat source under the condition of steady heat conduction is put forward by the function model of the temperature and depth. In view of the thermal anomaly of the surface temperature caused by the heat source in the Deep Coal Gangue Mountain, a set of theory and method based on the thermal infrared technology and the close range photogrammetry is proposed, which have the following understanding. (1) on the basis of the internal objective condition similarity principle of spontaneous combustion of Coal Gangue Mountain, a field simulation experiment of active temperature field of Coal Gangue Mountain was designed. Based on the measured temperature data, the temperature distribution law of deep horizontal direction of Coal Gangue Mountain was revealed. The rule is as follows: (1) under the condition of different heat sources, each horizontal layer, heat source with the passage of time. The influence area range is increasing gradually, the temperature of the affected region is also increasing. When the heat source temperature is stable for a certain period of time, the temperature of the affected area of the heat source tends to stabilize basically. (2) the vertical direction distance from the heat source center 0-0.6m horizontal layer, the influence radius of the heat source is about 0.3m, which affects the regional temperature increase within the radius less than that of the heat source. It is obvious that the temperature of the region outside the radius is floating around 15-25. This indicates that the thermal conductivity of the coal gangue is poor. In order to locate the heat source by using the temperature probe, the temperature probe should be properly placed to realize the accurate location of the heat source position. At the same time, with the distance from the heat source increasing, the temperature of each level layer is gradually reduced and the heat conduction is carried out. The study found that the measurement point at the 0.1M level above the heat source is higher than that at the horizontal surface of the heat source, and the temperature rise is faster. The reason may be that the uneven temperature distribution in the Gangue Mountain is uneven and the air density field is formed. The air density field produces floating lift and forms the inner space between the space. The flow heat transfer, due to the small internal gap, is characterized by the heat diffusion effect, which causes the heat transfer to mean the heat transfer process, which leads to the higher temperature. Therefore, the convection in the vertical direction and the heat dispersion effect in the vertical direction are stronger than the horizontal direction; 4. Quantificationally reveals the heat source strength, the horizontal layer height and the temperature rise rate of three. According to the function relation of the three, the temperature rise rate is retrieved, the maximum error is 0.86 and the minimum error is 0. 5. The analysis of the change law of the temperature loss rate is that the temperature loss rate decreases rapidly in depth 0-0.2m, and the temperature loss rate increases with the depth of 0.2-0.6m, which is the lowest at the depth of 0.2m, and the level can be seen. The thermal dispersion effect of 0.2m is the most obvious and most intense. (2) the distribution of temperature in the vertical direction of the Deep Coal Gangue Mountain is revealed. The temperature variation analysis of each measuring point above the heat source is found to be in the range of heat source 0-0.6m, the temperature rises greatly, and the temperature is greatly influenced by the heat source; in the range of 0.6-1m from the heat source, the heat source affects the temperature within this range. In the range of heat source 1-1.5m, the influence of the temperature on the heat source decreases sharply, and the ambient temperature begins to influence the region gradually, especially when the heat source is low, which reacts when the Coal Gangue Mountain is in the initial stage of oxidation and exothermic, and the heat source is more difficult to detect. The location of the point is to monitor the temperature rise of each point in real time to determine whether there is a high temperature source. In the range of 1.5-1.8m, the temperature varies regularly with the ambient temperature. Therefore, the influence of the internal and external factors should be considered comprehensively, if the temperature of the shallow or surface points is predicted by the temperature of the shallow or surface points. In order to avoid the depth affected by ambient temperature, a temperature stratification model of the active temperature field in the Deep Coal Gangue Mountain is proposed based on the above results. The surface, boundary layer, inner layer, surface 0-0.3m range of the surface of the surface of the surface of the Gangue Mountain are in turn, and the area is affected by the temperature of the outside environment. The temperature distribution of each measuring point on the vertical axis of the two distance heat source 0.2m shows that the thermal dispersion effect is most obvious in the vertical direction to the heat source 0.2m, and the temperature of the measuring point on the vertical axis of the heat source 0.2m is about two times lower than the temperature of the measuring point above the heat source. Therefore, it should be taken in advance in the treatment of the spontaneous combustion fire source by the use of the grouting fire extinguishing method. Using scientific and reasonable technical means to prejudge the position of the deep fire source, the temperature of the fire source can be detected and the location of the fire source is accurately located through the vertical direction of the hole. In addition, the heat of the heat source needs a large amount of accumulation, accumulation, and point continuous slices to form a region. When the temperature of the area reaches a burning point, it causes spontaneous combustion. Therefore, it is possible to deduce that the first spontaneous combustion in the Coal Gangue Mountain should be a small area, not just a point. (3) quantitative analysis of the intensity of heat sources and the maximum impact range, The relationship between the farthest propagation distance is found to be a power function relationship between the intensity of the heat source and the maximum influence range and the farthest distance. F (x) =-296.7x-1.072+2.089, fO) = 2.05*10-6x2.274+0.6506, according to the quantitative relationship, the maximum influence range and the farthest distance of the heat source can be predicted, and the detection and determination of the subsequent fire source can be obtained. 4. (4) to build a deep temperature field inversion model (1). In the case of "unsteady heat conduction" in the waste rock mountain, a functional relationship model of heat source temperature and depth is proposed: T = a. EB (X-D) + C. This model can effectively predict the minimum depth of potential heat source point in the deep Gangue Mountain and predict the heat source temperature at different depths. Under the condition of "steady heat conduction" in the Gangue Mountain, the depth inversion model of the heat source is proposed based on the heat conduction theory. The study shows that the maximum error of depth model inversion is 0.087m and the minimum error is 0.06m. Thirdly, the heat source temperature inversion model is put forward to the heat source under the condition of "steady heat conduction" in the waste rock mountain. The temperature inversion is divided into three steps, first using the depth inversion of the heat source depth, using the surface energy heat balance equation to inverse the boundary layer temperature Td, and then the temperature of the depth and the upper boundary layer as the initial value, based on the proposed heat source temperature and depth exponential growth relation function T=Td. B.A. (Rd) +c, inversion of the heat source temperature, finally profit. Using the measured temperature data to verify the reliability and accuracy of the model, it is found that the maximum error of the model inversion is 6.82, and the maximum relative error is 2.62%. (5). The principle and method of building the surface temperature field of the spontaneous combustion coal gangue mountain is put forward (1) the surface temperature distribution analysis of the surface of the coal gangue is found to be influenced by the ambient temperature and the solar radiation. With the increase of the distance from the surface of the Gangue Mountain, the temperature is weakened by the influence of the ambient temperature. This study, based on the thermal infrared technology and close range photogrammetry, proposes a set of joint construction of the surface temperature field of the coal gangue hills, based on the thermal infrared technology and the close range photogrammetry. The principle and method, through the location of the surface thermal anomaly area to make a reasonable prejudgment of the situation of the deep combustion, and then combine the deep temperature field inversion model to locate the heat source distribution and position. The study shows that the maximum error of the space coordinate maximum point of the constructed surface temperature field is 0.014m, and the minimum point error is 0.005M; The concept model of deep temperature based on surface temperature is proposed. First, the thermal anomaly area is determined according to the surface temperature field of the Coal Gangue Mountain surface, and the surface temperature is used to inverse the boundary layer temperature through the surface temperature. Finally, the inversion model of the deep temperature field is used to reverse the temperature and depth of the heat source, and it can effectively locate the heat. It is a long-term and arduous task to control the spontaneous combustion of coal gangue mountains, especially for the mastery of deep combustion and fire source positioning technology. This study provides an exploratory understanding for the exploration of the deep temperature distribution in the coal gangue mountains, and the inversion of the deep temperature field for the construction of deep temperature field. The model lays the foundation, because the combustion in the Coal Gangue Mountain is extremely complex and is restricted by the experimental conditions, many understandings and explorations have certain limitations. In the future, the combustion state of different heat sources and the different distribution positions should be studied in depth to provide more scientific reference for the localization technology of spontaneous combustion coal gangue mountain fire source. The green development of the ecological environment in the mining area.

【学位授予单位】：中国矿业大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD752.2

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