微生物技术治理瓦斯可行性分析及应用研究

针对渝阳煤矿低透性、突出性的M_8煤层,提出一种改变过去被动治理瓦斯的微生物处理瓦斯的新技术,对新技术进行可行性研究以及现场试验研究。研究表明:(1)发现甲烷氧化菌M02-019具有较好的利用价值,并利用小型放大实验验证了其在井下煤岩体中具有较好的处理瓦斯能力,瓦斯处理可分为4个阶段并且最终瓦斯降解率可达90%以上;(2)现场试验证明,微生物甲烷氧化菌M02-019具有较好的瓦斯治理效果,能迅速降低煤层瓦斯含量和瓦斯压力,可供类似矿井借鉴。     

利用微生物技术治理煤矿瓦斯的研究展望

目前,我国的煤矿瓦斯防治技术主要为通风、抽放等物理方法,该类方法仍不能完全满足防治煤矿瓦斯灾害的安全要求。笔者提出一种治理煤矿瓦斯的新思路,采用一种新的控制方法,试图通过生物技术使瓦斯涌出量减少,防治煤矿瓦斯灾害。为此,对应用微生物技术治理煤矿瓦斯的可行性进行了分析,简单介绍了甲烷氧化菌的氧化机理及其在其他领域的应用,并通过初步试验对甲烷氧化菌降解煤样瓦斯的效果进行了测定,从而对其有了感性的认识,在已有的对甲烷氧化菌的研究和初步试验的基础上,对应用甲烷氧化菌解决煤矿瓦斯危害进行了展望。     

大力开发利用煤气层促进瓦斯产业发展

矿井瓦斯是矿井中主要由煤层气构成的以甲烷为主的有害气休,是在煤的生成和煤的变质过程中伴生的气体.瓦斯,又称为煤层气,其实是吸附在煤层中的一种非常规天然气,其主要成分和天然气一样,实际上是一种热值高、无污染的优质的新型清洁能源,可用于发电燃料、工业燃料、化工燃料和居民生活燃料.瓦斯事故是我国煤矿安全事故居高不下的主要矛盾,有效控制瓦斯事故是解决中国煤矿安全问题的关键.     

矿井回风流中低浓度瓦斯利用现状及前景

矿井回风流瓦斯直接排放到大气中 ,不仅造成了资源的浪费 ,而且加剧了温室效应 ,如何利用低浓度瓦斯是迫切需要研究的课题。介绍了矿井瓦斯利用存在的主要问题 ,介绍了作为辅助燃料和主要燃料在国外的研究利用情况 ,重点介绍了TFRR的原理、反应过程及热量的回收利用方式 ,并对低浓度甲烷的应用前景进行了展望。     

谈谈矿井瓦斯抽放

瓦斯抽放是治服煤矿井下瓦斯灾害的一种有效措施,随着煤炭生产的不断发展和矿井的不断延伸,瓦斯涌出量也随之增多,这项工作已经越来越显得重要。目前,我国煤矿已有数十对矿井进行瓦斯抽放,今后我们还要进一步开展这项工作,使所有有条件抽放瓦斯的矿井都这样做。 矿井瓦斯的性质及其危害 矿井瓦斯是指从煤层中以及生产过程中涌出的各种有害气体的总称。矿井瓦斯的主要成分是甲烷(CH4),所以煤矿一般说的瓦斯就是指甲烷,又叫沼气,它是无色、无味、无臭的气体,对空气的比重为0.554,比空气轻一半左右,容易积存在巷道顶部或掘进工作面的上山迎头…     

真空紫外光降解瓦斯反应动力学规律

为了研究真空紫外光降解瓦斯过程的反应动力学规律,在自制的真空石英光化学反应器中以含甲烷标准气体模拟矿井瓦斯,运用Langmuir-Hinshelwood(L-H)拟一级反应动力学模型对不同光照强度、氧气体积分数、甲烷初始体积分数和水分子体积分数下瓦斯(甲烷)的降解过程进行拟合.结果表明:真空紫外光降解瓦斯反应动力学规律符合一级反应动力学特性;光照强度、甲烷初始体积分数、氧气体积分数和水分子体积分数是影响真空紫外光降解瓦斯的主要因素;瓦斯(甲烷)降解的反应速率随光照强度和氧气体积分数增大而增大,随甲烷初始体积分数增大而减小,随水分子体积分数增大而先增大后减小.     

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…     

厌氧微生物降解矿井瓦斯的特征实验研究

采场煤体是历经反复多次的沉降、变质过程之后形成的稀氧甚至缺氧、且含甲烷的复杂地质体。为了实现煤体被采掘之前甲烷降解效率的最大化,从淹水水稻田20 cm深土壤中取泥样,利用NMS培养基通过培养、分离、纯化得到了目标厌氧型甲烷氧化菌株;然后分别控制变量——温度、p H值和甲烷浓度,利用气相色谱仪测定了气样中甲烷的含量,分光光度计测定了菌样的OD600值。结果表明,在30℃、p H为6～7的条件下菌株降解甲烷的能力最强,且具有降解更高浓度甲烷的潜力。实验结果将在一定程度上丰富和完善微生物治理矿井瓦斯的理论体系,并促进其应用技术的推广和应用范围的拓展。     

金地井田煤层瓦斯分布规律研究及工作面瓦斯涌出量预测

掌握煤层瓦斯分布规律是保证矿井安全生产的必要技术条件之一。根据金地井田的地质构造特征,由现场实测8号、13号煤层瓦斯含量和气体组分实验室分析测定结果,结合煤层瓦斯垂直分带理论,判定金地井田范围内8号、13号煤层均处于瓦斯风化带。应用分源预测法,对金地井田不同生产时期的回采工作面瓦斯涌出量含量进行预测,认为受井田中东部大面积13号煤层隐伏露头影响,8号、13号煤层处于瓦斯风化带中的氮气-甲烷带,但无法进行瓦斯变化样度计算。该研究可为该矿井投产后瓦斯安全管理提供量化参考。     

煤矿建设项目安全设施审查验收部分内容修改

本刊讯11月21日,国家煤矿安全监察局发布通知,对《煤矿建设项目安全设施设计审查与竣工验收报告书》中的矿井开拓与开采中的安全出口、瓦斯灾害防治的矿井瓦斯等级、矿井通风、防治水、电气系统等部分内容进行了修改,同时增加了距掘进工作面30～50m范围内,应安设电话;     

基于非分散红外技术的煤矿井下有害气体定量探测方法研究

煤矿井下有害气体的浓度监测对煤矿生产安全预警至关重要。介绍了一种基于非分散红外光谱技术能够同时定量探测煤矿井下一氧化碳、甲烷等有害气体的方法。入射红外光经过高速旋转的滤光轮,得到各种待测气体相应滤波通道的调制光信号,经怀特池中待测气体吸收后得到各种气体的吸光度。通过非线性最小二乘拟合吸收光与被测气体浓度,得到测量系统的浓度定标曲线,一氧化碳、甲烷和二氧化碳三者定标拟合相关系数分别为0.9992、0.9996和0.9998。分析了系统的测量精度,通过比较样气标准浓度与实测浓度大小,发现所有被测气体的这两组数据的相关性均大于0.998,测量误差均小于5%。实验结果表明,采用非分散红外光谱技术可以实现煤矿井下多组分有害气体的同步精确探测,为扩展煤矿安全预警技术手段提供了参考。     

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.     

Vessel outflow sensitivity to composition

The vessel composition is important when considering vessel outflow because changes in composition change the density and potentially more importantly change the shape and location of the boundary of the two-phase envelope. The influence on the phase boundary can be significant on vessel outflow as the liquid phase density is typically two orders of magnitude larger than the gas phase density for pressures and temperatures remote from the thermodynamic critical point. In this article two issues are addressed, outflow sensitivity to composition of hydrocarbon systems with a large component of methane, and outflow from systems where a petroleum fraction representation of composition is used. It is shown that approximating multi-component systems with a large methane content by methane can result in significant discrepancies in the predicted mass flow rate and vessel pressure. When a vessels composition is characterised by petroleum fractions, and the Kesler–Lee equations are used to predict thermodynamic properties, the predicted outflow is almost comparable to the predicted outflow calculated using a mole fraction representation of composition.     

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.     

Experimental research on displacing coal bed methane with supercritical CO2

The high-gas and low-permeability are the common problems of China coal mine, which restrain the mining of coal-seam gas resources safely and efficiently. Hence, to solve the problem of low permeability of coal seam, an experimental system was set up and experimental research was conducted to investigate the effect of the displacement of methane by injecting supercritical CO₂ into coal samples. The experimental results indicated that, the extraction effect of supercritical CO₂ changes the coal’s porosity, and broadens the seepage channel for methane. Thus, the methane could be desorbed effectively from the coal matrix, and flow through more cracks at higher speed.     

Experiments and numerical simulation on methane flame quenching by water mist

The study of extinguishment using water mist has been motivated due to the phase-out of the use of halens and the search for alternative means that preserve all of the benefits of a clean total flooding agent without adverse environmental impact. With the numerical simulation, we analyzed a gas–liquid two-phase problem including water (liquid), air and methane (gas) using Eulerian equations for the liquid phase and the full Navier–Stokes equations for the gas phase. Gaseous mass, momentum and energy equations are integrated simultaneously by a Harten–Yee explicit non-MUSCL modified-flux type TVD scheme for the convective terms and a central difference scheme for the viscous terms. Liquid phase conservation equations are solved with an application of a flux-vector-splitting scheme. In the experiments in an open room (500×500×500 mm) we observed an interaction of the diffusion flame with the water mists. The results show remarkable flame quenching and a good agreement between the numerical and experimental results.     

高位巷瓦斯抽采下采空区自燃危险性数值分析及应用

针对大流量高位巷瓦斯抽采可能诱发采空区自燃问题,以南山矿18层5分段综放面为研究背景,构建采空区气体渗流分析模型。利用变渗透系数和Forchheimer方程,求解非线性流与层流并存下采空区三维氧气分布。结果表明:高位巷瓦斯抽采使工作面氧气更易沿漏风方向采空区纵深发展,氧化带总体宽度会随抽放流量的提高而增加。在进风侧氧气分布后移程度较小,而回风侧受抽放负压显著影响,出现明显氧气富集区。上下隅角封堵配合注氮,会降低抽放对氧气渗入的诱导影响。依据研究结论,利用综合防火措施消除了高位巷附近潜在的自燃危险。     

基于变压吸附原理的上隅角低浓度瓦斯处理技术研究

针对煤矿瓦斯气体容易在上隅角位置积聚，造成煤矿安全隐患这一难题，提出并设计了用变压吸附方法（PSA）分离瓦斯，降低上隅角瓦斯浓度的试验方案。依据相似原理及东庞煤矿实际工作面相关参数制作了U型通风系统采煤工作面及采空区模型。采用抽出式通风，向巷道混入甲烷气体，进行了相关的模拟实验。吸附设备正常工作时，上隅角位置的甲烷浓度能由1．1％～1．2％降低到0．7％-0．8％左右，该方法在解决上隅角甲烷积聚问题上能够起到积极作用。