神东矿区综采工作面采空区常温条件下CO产生与运移规律研究及应用

发布时间：2018-04-27 00:35

本文选题：煤常温氧化 + CO产生规律　；参考：《太原理工大学》2015年博士论文

【摘要】：神东矿区是我国13个亿吨矿区之一，所属矿井均为全国一流的现代化高产高效矿井，公司年产煤炭达2亿吨，主要开采的煤种为变质程度较低的长焰煤和不粘煤，开采煤层均为容易自燃和自燃煤层。由于矿井产量大、采空区面积大、煤层极易氧化等原因，，综采面回风隅角经常出现CO积聚并导致CO持续超限（超过《煤矿安全规程》规定的最高允许浓度24ppm），干扰煤自燃预测预报，同时给现场制定科学有效的防灭火和综采面回风隅角CO管理和控制措施带来了困惑，严重影响矿井安全生产。综采面采空区CO产生规律、积聚及运移规律一直是矿井火灾防治的关键科学问题，论文以神东矿区为研究对象，围绕煤煤常温氧化CO产生规律，采空区CO积聚、运移规律，综采面回风隅角CO安全及自燃预警浓度，CO控制技术和管控标准开展研究，为解决长期困扰我国西北、华北等重点产煤基地日常生产中CO超限与自然发火关系的问题，制定符合现场实际的矿井防灭火技术管理标准提供依据。得到以下主要结论：（1）通过理论分析、现场观测发现，神东矿区综采面生产期间回风隅角CO较检修期间超限严重，相比CO浓度高出约10～20ppm。留顶煤采煤方法CO超限最为严重，一次采全高工作面基本上未产生CO超限。神东矿区综采面回风隅角CO来源是采空区浮煤常温氧化、胶轮车尾气、采煤机割煤破碎煤体产生，其中采空区浮煤常温氧化是主要来源。采空区浮煤常温氧化造成工作面回风隅角CO浓度达80～150ppm，占76%；密集车辆时间段胶轮车尾气造成工作面回风隅角CO达10～20ppm，占18%；采煤机割煤破碎煤体造成工作面回风隅角CO达10ppm，占6%。（2）通过现场采样、实验室分析对神东矿区开采煤层原始赋存CO含量进行了测定，结果表明：神东矿区煤层中原生赋存的CO含量极少，含量在0.42～0.52×10-6cm3/g，由于神东矿区综采工作面配风量较大，在1000～3000m3/min变化，因此，煤层中原生赋存的CO不会导致综采面回风隅角CO持续超限。（3）研制开发了煤常温氧化实验装置，现场采样，并进行了5个典型煤层煤样（1.3kg）常温封闭氧化试验。研究结果表明：神东矿区煤在小于20℃的常温环境下能产生CO并消耗一定量的O2，在温度基本保持不变的条件下，CO浓度逐渐升高，一定时间后达到一定浓度值后保持稳定，煤样产生CO浓度最大值为154～425ppm，浓度稳定时间一般在380～980min。随着氧化的进行，产生CO速率逐渐下降，下降到一定程度后CO的累积浓度不再上升，稳定在一定的水平。各煤样产生CO速率平均为0.56～1.64cm3/（min·m3）。消耗O2速率和生成CO速率呈正比，不同煤样消耗O2速率不同，一般为0.36～1.30l/（min·m3）。（4）通过对煤常温下惰性气氛下CO脱附实验和氧化环境下的多次氧化实验研究，发现煤解吸与煤氧化过程中的CO释放速率具有相似的过程，第一个小时内CO的释放速率锐减，一段时间之后，CO释放速率的减少趋势放缓，并逐步趋于稳定，并通过研究发现，煤的常温氧化是CO释放的主要原因。常温氧化实验过程中CO释放速率的倒数与时间的对数成线性关系,因此CO的释放速率与时间的关系可表示为RCO=a/lnt-b,可通过此公式可定量的研究CO释放速率与氧化时间关系。 (5)煤常温下多次氧化实验表明：CO的释放速率除了受到氧气浓度和煤体表面活性位点的影响外,主要受到煤氧产生抑制反应的氧化产物影响。当这些氧化产物排空消除后,煤氧反应进程重新恢复,CO释放速率上升。这一结论证明采空区浮煤反复在采空区漏风流的作用下不断地产生CO并随着采空区漏风运移到工作面回风隅角,从而导致综采面回风隅角CO持续超限。 (6)通过建立基于氧气消耗速率与氧气浓度的关系函数,获得了煤常温下CO产生机理,煤的常温氧化机制分为五个阶段——“化学反应控制机制”、“过渡期”、“扩散控制机制”、“抑制控制机制”和“类燃烧反应机制”研究结果可以为综采面回风隅角CO超限治理提供理论依据。 (7)通过对综采工作面采空区CO、O2气体的现场观测,并结合煤常温氧化实验结果,确定了采空区CO产生的危险区域,采空区中CO气体浓度在距离工作面60～100m的位置出现最大值,一般在71～230ppm间,然后在120m稳定,CO在50ppm以内。 (8)通过建立工作面不同推进位置时的3D气体运移CFD模型,研究分析了U型通风工作面气体分布特征,在此基础上,模拟分析了U型通风工作面采空区不同位置煤氧化产生CO气体在采空区的分布特征,得出了CO气体在采空区的运移规律。 (9)在大量的实验和现场观测的基础上,建立了神东矿区综采面回风隅角CO安全及自燃预警浓度预测模型：利用该模型计算确定了神东矿区综采面回风隅角CO安全及自燃预警浓度值,并与现场测定结果相吻合。确定了神东矿区综采工作面正常回采时回风隅角CO安全浓度为85ppm,自燃预警浓度为350ppm。 (10)在对神东矿区开采技术条件及煤自燃特点,在大量现场观测、实验室研究、理论分析计算的基础上,结合神东矿区现有的防灭火技术装备条件,编制了《神东矿区防灭火管理规定》。该管理规定给神东矿区防灭火工作提供了科学的依据,对神华集团及我国类似条件矿井防灭火技术管理具有借鉴意义。
[Abstract]:The Shendong mining area is one of 13 million ton mining areas in China. All the mines belong to the first-class modern high production and high efficiency mine in China. The company produces 2 million tons of coal annually. The main coal mining is long flame coal and non stick coal with low metamorphic degree. The coal seam is easy to burn and spontaneous combustion coal seam. Because of the large coal mine production, the large area of goaf and the coal seam pole Because of easy oxidation and other reasons, CO accumulation often occurs in the corner corner of the fully mechanized mining face and leads to the continuous overlimit of CO (exceeding the maximum allowable concentration of 24ppm stipulated in the coal mine safety regulations >). It interferes with the prediction of coal spontaneous combustion and brings puzzles to the field of making a scientific and effective fire prevention and recovery corner CO management and control measures, which seriously affect the mine. Safety production. The rule of CO production in the mining area of fully mechanized mining area, accumulation and migration law is the key scientific problem in mine fire prevention and control. The thesis takes the Shendong mining area as the research object, around the coal coal coal at normal temperature oxidation CO rule, the accumulation of CO in the goaf, the migration law, the CO safety and spontaneous combustion early warning concentration in the corner corner of the fully mechanized coal face, CO control technology and control In order to solve the problem of the relationship between CO overlimit and natural fire in the daily production of key coal producing bases in Northwest China, North China and other key coal production bases, the standard development research provides the basis for making the mine fire prevention and extinguishing technology management standards in line with the actual field. The following main conclusions are obtained:
(1) through the theoretical analysis, the field observation shows that the CO of the return air corner of the fully mechanized coal mining face during the production of the Shendong mining area is more serious than the overhaul during the maintenance period. Compared with the CO concentration higher than the concentration of 10 to 20ppm. with the top coal mining method, the CO overlimit is most serious, and the first full height working face has not produced the CO exceeding the limit basically. The origin of the corner corner of the return air in the fully mechanized coal mining face in Shendong mining area is the floating area floating area floats. Coal at normal temperature oxidation, rubber wheel vehicle tail gas and coal shearer broken coal are produced. The main source is the atmospheric oxidation of coal floating coal at normal temperature in goaf. The CO concentration of the return air corner of the working face is 80 ~ 150ppm, accounting for 76%, and the exhaust gas of the time section of dense vehicles is 10 to 20ppm, accounting for 18%, and the coal mining machine. The CO of the working face return to the wind can reach 10ppm, accounting for 6%.
(2) through field sampling, the original CO content of coal seam mining in Shendong mining area was measured by laboratory analysis. The results showed that the original CO content in coal seam in Shendong mining area was very small and the content was 0.42 to 0.52 x 10-6cm3/g. Because of the large amount of air distribution in the fully mechanized coal mining face in Shendong mining area, the change of the coal seam was 1000 to 3000m3/min, so the coal seam was born in Central China. The stored CO will not lead to continuous overrun of CO in the return corner of fully mechanized face.
(3) the experimental equipment for oxidation of coal at normal temperature was developed and sampled, and 5 typical coal seam coal samples (1.3KG) were tested at normal temperature. The results showed that the coal in Shendong mining area could produce CO and consume a certain amount of O2 under the ambient temperature less than 20 C, and the concentration of CO increased gradually when the temperature base was kept unchanged. After a certain concentration is reached, the maximum CO concentration of coal sample is 154 ~ 425ppm, and the time of concentration stability is generally 380 ~ 980min. with oxidation, and the rate of CO decreases gradually. After a certain degree, the cumulative concentration of CO is no longer rising and stable at a fixed level. The average CO rate of each coal sample is 0.56 ~ 1.64. Cm3/ (min. M3). The rate of O2 consumption is proportional to the rate of CO formation, and the rate of O2 consumption of different coal samples is different, generally 0.36 to 1.30l/ (min. M3).
(4) it is found that the release rate of CO in the process of coal desorption and coal oxidation has a similar process by CO desorption experiment under inert atmosphere at normal temperature and oxidation environment, and the release rate of CO decreases sharply in the first hour. After a period of time, the decreasing trend of CO release rate slows down, and gradually tends to stabilize, and pass through. After study, it is found that the oxidation of coal at normal temperature is the main reason for the release of CO. The reciprocal of the release rate of CO in the process of atmospheric oxidation is linear with the logarithm of the logarithm of time, so the relationship between the release rate of CO and the time can be expressed as RCO=a/lnt-b, and the relation between the release rate of CO and the oxidation time can be quantitatively studied by this formula.
(5) multiple oxidation experiments at coal at normal temperature show that the release rate of CO is mainly influenced by oxygen concentration and the surface active site of coal, which is mainly influenced by the oxidation products of coal oxygen inhibition. When these oxidation products are eliminated, the process of coal oxygen reaction is resumed and the release rate of CO rises. This conclusion proves that the goaf is in the goaf. The floating coal constantly produces CO under the action of leakage flow in the goaf, and moves to the corner of the return air in the working face with the air leakage in the goaf, which leads to the continuous overlimit of the CO in the return corner of the fully mechanized face.
(6) by establishing a relationship function based on oxygen consumption rate and oxygen concentration, the mechanism of CO production at normal temperature is obtained. The mechanism of coal atmospheric oxidation is divided into five stages: "chemical reaction control mechanism", "transition period", "diffusion control mechanism", "inhibition control mechanism" and "type combustion reaction mechanism" results can be found. It provides theoretical basis for CO overrun in the corner of fully mechanized mining face.
(7) through the field observation of CO and O2 gas in the goaf of fully mechanized coal mining face, and combining with the experimental results of coal atmospheric oxidation, the dangerous area produced by CO in the goaf is determined. The maximum value of CO gas concentration in the goaf is in the range of 60 to 100m from the working face, usually between 71 and 230ppm, and then in 120m and CO in 50ppm.
(8) through the establishment of the 3D gas migration CFD model in different position of the working face, the gas distribution characteristics of the U ventilation face are studied and analyzed. On this basis, the distribution characteristics of CO gas in the goaf are simulated and analyzed in different positions of the goaf of the U ventilation working face, and the migration law of CO gas in the goaf is obtained.
(9) based on a large number of experiments and field observations, a prediction model for early warning of CO safety and spontaneous combustion in the corner of fully mechanized mining face in Shendong mining area is established.
The early warning concentration of CO safety and spontaneous combustion in the return air corner of fully mechanized coal mining face in Shendong mining area is calculated by this model, and it is in agreement with the results of field measurement. The safety concentration of CO in the corner of the return air corner of the fully mechanized coal mining face in Shendong mining area is 85PPM, and the early warning concentration of spontaneous combustion is 350ppm.
(10) on the basis of a large amount of field observation, laboratory research, theoretical analysis and calculation on the technical conditions and coal spontaneous combustion characteristics of Shendong mining area, combining with the existing conditions of fire prevention and extinguishing technology and equipment in Shendong mining area, the regulations for the management of fire prevention and extinguishing in Shendong mining area have been compiled. The management rules provide a scientific basis for the fire prevention and extinguishing work in the Shendong mining area. It has reference significance for Shenhua Group and similar mine in China.

【学位授予单位】：太原理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TD752.2

【参考文献】