分布式光纤传感瓦斯气体系统的研究

根据激光吸收光谱技术原理,瓦斯气体分子在一定的波段对光有吸收特性,使光谱具有显示瓦斯的特性,通过比较,反演出瓦斯气体在矿井中的浓度。分布式光纤传感瓦斯气体系统是利用空分复用技术,采用多个气体吸收型光纤传感器,并通过谐波检测技术对瓦斯信号进行处理。试验研究表明,该传感器的精确度和稳定性均可满足实际要求,该系统只有光纤在井下,所有的电子处理设备全部在地面,因此,安全性得到了极大的提高,适用于我国煤矿瓦斯监测预警的在线、实时的快速系统。     

光声光谱火灾气体探测系统

气体是火灾中最早出现的燃烧产物,利用燃烧过程中产生的气体作为判据能在很大程度上提高火灾探测及预警的早期性。光声光谱技术由于其在气体检测领域的高灵敏度、宽检测范围等优点已成为火灾探测的一个重要的发展方向。介绍了光声光谱技术原理,设计了一套基于光声原理的火灾气体探测系统。对该系统的基本性能进行了测试,并对棉绳阴燃和聚氨酯泡沫明火实验中产生的气体浓度(CO)进行了测量,根据光声信号的变化并结合一定的算法反演得到了这两组实验中CO的浓度变化曲线。实验表明,该探测系统对火灾能够很好地响应,能够满足探测需求。     

矿井通风

在我国,几乎所有的煤矿和部分非煤矿山都是地下开采,矿井通风状况的好坏直接关系到井下开采的安全,关系到井下作业人员的健康和生命安全。所以搞好矿井通风工作是地下开采的重要环节。 一、矿井通风的目的 (一)降低有毒有害气体和粉尘的浓度 矿床开采过程中,经常产生或渗出有毒有害气体。在煤矿,主要有沼气(CH_4)、一氧化碳(CO)、二氧化硫(SO_2)、二氧化氮(NO_2)、硫化氢(H_2S)和氢气、氢气等。有些有毒有害气体达到一定浓度,对人体会产生不同程度的影响,如出现头痛、呕吐、丧失知觉等症状,以至死亡。此外,沼气达到一定浓度时,如果氧气…     

矿井瓦斯与煤尘

瓦斯和煤尘事故,是煤矿生产中的重大灾害。研究预防瓦斯、煤尘事故的对策,教育职工认识瓦斯、煤尘事故的规律,具有极其重要的意义。 矿井瓦斯 矿井瓦斯是井下有害气体的总称。凡是从煤层、岩层采空区中放出的气体 以及生产过程中产生的各种气体,统称为矿井瓦斯。组成矿井瓦斯的气体有;沼气(甲烷)、二氧化碳、氮,还有少量的乙烷、乙烯、氢、一氧化碳、硫化氢和二氧化硫等。由于矿井瓦斯中沼气约占80～90%,因此,煤矿职工习惯把沼气叫做瓦斯。 沼气无色、无臭、无味,比空气轻,本身无毒性。但是,当空气中沼气的体积浓度达43%时;空气中的氧含量下…     

基于单片机甲烷浓度监测的研究

设计了一种基于单片机来实现的甲烷浓度检测和报警功能的系统,该检测系统以AT89S52单片机为核心,包括有电源电路、传感器采集电路、信号放大电路、红外遥控电路、声光报警电路、显示电路等功能模块组成,通过传感器采集电路采集信号,输出与甲烷浓度对应电压信号,把电压信号进行A/D转换后送入单片机,经单片机处理后驱动器显示出被测气体甲烷浓度值,若被测甲烷浓度大于报警电路预设数值,报警电路发出报警,可以及时切断供电系统,防止瓦斯爆炸事故的发生.该系统采用高精度敏感元件,集成运算放大器INA128,ADc0809,以及远距离高可靠性通信芯片,且具有高速的处理能力,是一种电路设计新颖,参数测量准确,操作方便的甲烷浓度报警监控系统,实现了数字瓦斯气体的实时监控.为实现数字化井下测控和可视化综合管理提供了切实可行的方案.     

井下光谱多参数分析系统开发

本系统基于气体浓度光学分析方法理论朗伯-比尔(Lambert-Beer)定律、光谱气体检测技术开发,实现了对煤矿火灾与瓦斯灾害超前预警、灾害产生的有毒有害气体实时监测和煤矿环境气体爆炸危险性辨识,对于煤矿灾害防治、救灾过程中杜绝次生灾害,保障煤矿工人及救护队员的生命安全,促进煤矿安全生产具有重要意义。     

青海两矿七人死于瞎指挥

在这里我们讲两起本不该发生的悲剧。 一起是青海省祁连县默勒煤矿立井5人中毒致3人死亡的重大事故。 ——1988年6月16日早班,该矿井下一台风机被烧坏,停止了通风。随着氧气的减少,一氧化碳等有害气体增加,在井下作业的民工们逐渐感到头晕恶心,不能再坚持作业。但承包人马如祥却仍然指挥民工下井。当时,井下情况愈发恶劣,加上不断放炮,一氧化碳等有害气体的浓度急剧升高。到了17日,下井作业的5名民工便中毒晕倒在井下。其中2人经抢救脱险,另3人终因严重缺氧而当场死亡。 另一起同类事故发生在青海格尔木农场马海农工商公司鱼卡煤矿。 ——该…     

矿井主要有害气体的危害及预防

矿井下的主要有害气体,有一氧化碳、二氧化氮和硫化氢。在煤矿、金属矿山、化学矿山、建材矿山、核矿山和轻工业矿山的生产中,经常出现这类有害气体的中毒事故。了解有害气体对人体的危害的预防措施,对减少或控制中毒事故的发生有重要意义。现对这三种主要的有害气体的危害和预防措施分述如下。 一、一氧化碳 一氧化碳就是常说的煤气。它是一种无色、无臭、无味、无刺激性的气体,比重0.967,比空气略轻。 井下除了着火时产生大量一氧化碳外,放炮是产生一氧化碳的主要原因。所以,它常与炮烟混在一起。一氧化碳非常容易和人体红血球里的血红蛋…     

非色散红外CO2飞机火警探测技术研究

提出了基于非色散红外吸收原理(NDIR)实时监测环境中CO2气体浓度变化进行火警探测的方法。根据高空大气环境的特殊性,探讨了基于NDIR的CO2气体探测技术应用于飞机上所面临的低温低压难题。进行了基于NDIR的红外CO2飞机火警探测器的两种结构设计,提出了基于CO2气体浓度监测的红外CO2飞机火警探测器的主要参数要求,研究了基于CO2浓度变化速率与变化值的火灾报警算法。     

天然气高压输送管道微量泄漏TDLAS检测技术理论研究

天然气输送管网规模随着城镇化进程加快而急剧扩大,高压管道气体微量泄漏的威胁日益严重,传统检测方法不能实现连续地精确检测。利用可调谐半导体激光吸收光谱(TDLAS)检测技术可以实现对微量泄漏的甲烷等气体进行快速、精确地检测。介绍了TDLAS技术的检测原理和压力管道的泄漏物理模型。选择CH4在1 653.7 nm处的吸收谱线为研究对象,结合已有的数据与参数,分析了光谱吸收率和可探测浓度下限随温度、压强的变化特征,以及激光扫描步长对测量精度的影响。结果表明,TDLAS技术应用于高压管道微量泄漏的实时检测是可行的。测量得到的气体浓度符合检测标准,可作为相关检测的基准值谱。     

Co-utilization of two coal mine residues: Non-catalytic deoxygenation of coal mine methane over coal gangue

The deoxygenation of coal mine methane (CMM) is a necessary process for concentrating methane by pressure-swing adsorption technology. Removal of oxygen in CMM by the reaction between oxygen and carbon in coal gangue is a novel solution for simultaneously utilizing two kinds of byproducts of coal mine, CMM and coal gangue. Process conditions for the deoxygenation of CMM were investigated systematically by using a fixed-bed reactor. The results show that higher temperature and lower gas flow rate not only decreased the residual oxygen concentration in the outlet gas but also increased the methane loss, and that the particle size of gangue did not influence deoxygenation within the experimental conditions used. Under optimal conditions (650 °C and 250 mL/min), there was no residual oxygen in the outlet gas and the methane concentration decreased by less than 0.5 mol%. XRD results show that coal gangue was activated during deoxygenation, and that activated gangue was suitable for utilization as a main component in cementitious materials.     

The influence of oxygen concentration on the composition of gaseous products occurring during the self-heating of coal and wood sawdust

This article deals with an assessment of the influence of oxygen concentration on the composition and amount of combustion products generated in the course of heating coal particles and wood sawdust at 150 °C. This was done both with normal air and at 15% oxygen in the air in an isothermal furnace. The generated gases were analyzed by a Fourier Transform infrared spectrometer. Results show that under both conditions, the same substances are formed: water, carbon dioxide, carbon monoxide and aliphatic hydrocarbons. However, the quantities changed. At 21% oxygen, the concentrations of carbon monoxide and methane were higher than at 15% oxygen both in coal and wood. The oxygen concentration was also found to affect the rates of release of CO and CO₂. The rate of release of CO was higher at 21% oxygen, but that of CO₂ was higher at 15%, indicating two different mechanisms. In all cases, the concentrations of these gases were higher for coal than for wood. The results have implications for the specification of safe conditions of storage of coal and wood substances and the selection of safety measures.     

中国煤矿安全技术进展

本文综述了我国在防治矿井瓦斯,矿井火灾和煤矿粉尘三个方面的技术概况。反映了为适应煤炭生产技术的发展,我国在这三方面的技术进展及所取得的效果。矿井瓦斯防治技术方面,主要介绍了矿井瓦斯涌出量的确定,瓦斯抽放工艺及装备,煤与瓦斯突出预测预报和综合防止煤与瓦斯突出技术的情况及成果。矿井火灾防治技术方面,着重介绍了矿井火灾预测预报技术,尤其是煤炭自燃发火早期预测预报技术以及煤矿自然发火防治技术中在灌浆代用材料,惰气防灭火等方面的发展及现状。煤矿粉尘防治技术方面,扼要介绍控制粉尘危险的基本途径,以防尘为中心包括降尘、除尘和防止煤尘爆炸及爆炸传播技术的一整套治理煤矿粉尘的工艺及装备,简要介绍了瓦斯煤尘爆炸的实验能力。通过本文的介绍,可以对我国在防治煤矿安全生产中主要自然灾害的技术对策和取得的成果有一个较全面的了解。     

市政污水检查井可燃气体组分及分布影响因素研究

为研究市政污水管网内主要可燃气体成分与分布,以实现其燃爆灾害的精准防控,本文采用现场检测的方法采集污水检查井内甲烷、氢气等5种可燃气体以及总的可燃气体浓度,统计分析污水管网各可燃气体的浓度范围,研究检查井深度和季节对甲烷浓度分布的影响。研究结果表明:污水检查井内甲烷浓度占比较大,一氧化碳、硫化氢、氢气和氨气所占比例较小;沿检查井深度方向,甲烷分布规律不尽相同,大部分检查井内甲烷随着与井口距离的增大呈逐渐增大变化趋势;季节对甲烷浓度变化影响较大,夏秋两季甲烷浓度较高,春季次之,冬季未检出甲烷。     

双波段可燃气体探测技术及其电路设计

介绍了双波段可燃气体探测技术，设计了探测装置。通过分析探测原理，对信号处理电路进行了改进。结果表明，双波段技术减小了环境因素的影响，非可燃气体对光线的阻挡，不产生误报。改进后的电路系统提高了信号稳定性和灵敏度。     

不同孔隙孔径碳材料对甲烷的吸附特征研究

为探究煤矿瓦斯气体吸附存在的孔隙孔径大小及煤矿瓦斯突出压力定为0.74 MPa的微观原因,采用计算化学材料软件Material Studio对碳材料孔隙孔径进行模型构建,通过Sorption模块计算不同碳材料孔隙孔径对甲烷的吸附情况,得到了单层和双层不同孔隙孔径碳材料对甲烷的吸附数据,然后用内插法得到0.74 MPa条件下单层和双层孔隙孔径碳材料对甲烷的吸附量。结果表明:单层和双层碳材料孔隙孔径对甲烷吸附的最佳孔径分别是10和8;0.74 MPa条件下不同孔隙孔径碳材料对甲烷的吸附量均在75%以上,对于最佳孔径甚至在90%以上。     

基于经典扩散模型不同粒径粒煤瓦斯扩散特征实验研究

为了获取多尺度粒煤在不同初始吸附平衡压力条件下的甲烷扩散特征，完成了0.25～1.00 mm，＞1.00～3.00 mm，＞3.00～6.00 mm和＞6.00～10.00 mm这4种粒径粒煤在1.0 和3.0 MPa初始吸附平衡压力下的甲烷扩散实验，并考察了经典扩散模型对各实验在0～10 min，0～60 min，0～180 min时间段的扩散拟合效果。研究结果表明:同实验时间，扩散率表现为随着粒径的减小呈增大趋势，0.25～1.00 mm相较＞6.00～10.00 mm粒径粒煤最大增大了73%；经典扩散模型不适用于描述甲烷在粒煤中的全阶段扩散，粒径越小拟合精度越低，仅对于初始扩散阶段（0～10 min）拟合效果较好；同初始吸附平衡压力，初始扩散系数D值随着粒径的增大呈递增趋势，＞6.00～10.00 mm相较0.25～1.00 mm粒煤扩散系数增大至7倍。不同尺度粒煤的瓦斯扩散特征，为煤层气达产、稳产、增产提供了储层改造方向。     

Study of coal oxidation behaviour in re-opened sealed heating

Possible changes in the oxidation behaviour of coal in the spontaneous combustion site of re-opened sealed heating were studied. Two samples of bituminous coal and three types of coal pre-treatment procedures were applied to simulate in situ conditions at the “spon-com” site: i) pre-oxidation of coal, ii) pre-heating of coal under inert gas, and iii) immersion of pre-heated coal in liquid water. Pre-treated samples were then examined for the production rate of the indication gases evolved during oxidation and for oxidation heat effects. Two main conclusions were drawn with respect to oxidation of the coal in re-opened sealed heating: i) carbon monoxide and unsaturated hydrocarbons maintain their relevance as spontaneous combustion indication gases, however, increased production of both carbon oxides can be expected; ii) coal in the extinguished spontaneous combustion site gains increased susceptibility to the self-heating process.     

Modified explosive diagram for determining gas-mixture explosibility

Determination of mine gas explosibility is definitely a significant work for mine safety especially when any mine rescue strategies are under planning or implementing. In detail, its importance can be well understood by the following two aspects: First, if a coal mine's production is under the normal conditions, the underground mine atmosphere must be monitored as a timely matter and its explosibility should also be determined shortly due to the continuous emission of methane or other combustible gases. Thus, the critical time which means a time period that combustible gases could build up to reach the lower flammable limit and then pass the upper flammable limit can be effectively watched and controlled. Second, when facing a mine rescue work or mitigating a hazard of mine accidents (gas explosion, coal fire, etc.), the explosibility determination is also very critical for miners' lives. In this paper, a widely used mine gas explosibility determination method, the Coward diagram, is going to be modified to improve its accuracy. The improvements made in this research effort include: (1) expanding the original Coward diagram; (2) correcting flammable limits; (3) redefining the nose limit for each combustible gas; (4) developing an equation to predict the excess amount of inert gas for individual combustible gas. Finally, the flowchart of the modified Coward explosibility diagram method is listed. By a cross-verification study, it shows that the modified Coward method has better accuracy and reliability and could be applied in practices.