Gas concentration monitoring system for small and medium-sized coal mines based on gas-sensing detection and single-chip control

This paper is aimed at the actual conditions of disaster caused by gas in small and medium-sized coal mines. A new gas concentration monitoring system for coal mines is developed on the basis of gas-sensing detection and single-chip control. The monitoring system uses the tin oxide as the main material of N-type semiconductor gas sensors, be- cause it has good sensitive characteristics for the flammable and explosive gas （ such as methane, carbon monoxide）. The QM-N5-semiconductor gas sensor is adopted to detect the output values of the resistance under the different gas con- centrations. The system, designedly, takes the AT89C51 digital chip as the core of the circuit processing hardware structure to analyze and judge the input values of the resistance, and then achieve the control and alarm for going beyond the limit of gas concentration. The gas concentration monitoring system has man）, advantages including simple in struc- ture, fast response time, stable performance and low cost. Thus, it can be widely used to monitor gas concentration and provide early wamings in small and medium-sized coal mines.

Microseismic Monitoring Data Fusion Algorithm and Coal and Gas Outbursts Prediction

The prediction study on coal and gas outbursts is carried out by monitoring some indices which are sensitive to the initiation of coal and gas outbursts. The values and changing roles of the indices are the foundations of coal and gas outbursts prediction. But now, only the data of ere key monitoring station is used in the coal and gas outbursts prediction practice, and the other data are ignored. In order to overcome the human factor and make full use of the monitoring information, the technique of multi-sensor target tracking is proposed to deal with the microseismic informatiion. With the results of microseismic events, the activities of geological structure, fracure-depth of roof and floor, and the location of gas channel are obtained. These studies indicate that it is considerably possible to predict the coal and gas outbursts using microseismic monitoring with its inherent ability to remotely monitor the progressive failure caused by mining.

In-situ measurement and distribution of flue gas mercury for a utility PC boiler system

The in-situ instrumentation technique for measuring mercury and itsspeciation downstream a utility 100 MW pulverized coal (PC) fired boiler system was developed andconducted by the use of the Ontario hydro method (OHM) consistent with American standard test methodtogether with the semi-continuous emissions monitoring (SCEM) system as well as a mobile laboratoryfor mercury monitoring. The mercury and its speciation concentrations including participate mercuryat three locations of before air preheater, before electrostatic precipitator (ESP) and after ESPwere measured using the OHM and SCEM methods under normal operation conditions of the boiler systemas a result of firing a bituminous coal. The vapor-phase total mercury Hg(VT) concentration declinedwith the decrease of flue gas temperature because of mercury species transformation from oxidizedmercury to particulate mercury as the flue gas moved downstream from the air preheater to the ESPand after the ESP. A good agreement for Hg°, Hg^(2+) and Hg( VT) was obtained between the twomethods in the ash-free area. But in the dense particle-laden flue gas area, there appeared to be abig bias for mercury speciation owing to dust cake formed in the filter of OHM sampling probe. Theparticulateaffinity to the flue gas mercury and the impacts of sampling condition to accuracy ofmeasure were discussed.

Application of a novel detection approach based on non-dispersive infrared theory to the in-situ analysis on indicator gases from underground coal fire

Coal mine fires,which can cause heavy casualties,environmental damages and a waste of coal resources,have become a worldwide problem.Aiming at overcoming the drawbacks,such as a low analysis efficiency,poor stability and large monitoring error,of the existing underground coal fire monitoring technology,a novel monitoring system based on non-dispersive infrared(NDIR)spectroscopy is developed.In this study,first,the measurement principle of NDIR sensor,the gas concentration calculation and its temperature compensation algorithms were expounded.Next,taking CO and CH_(4) as examples,the liner correlation coefficients of absorbance and the temperature correction factors of the two indicator gases were calculated,and then the errors of concentration measurement for CO,CO_(2),CH_(4) and C_(2)H_(4) were further analyzed.The results disclose that the designed NDIR sensors can satisfy the requirements of industrial standards for monitoring the indicator gases for coal fire hazards.For the established NDIR-based monitoring system,the NDIRbased spectrum analyzer and its auxiliary equipment boast intrinsically safe and explosion-proof performances and can achieve real-time and in-situ detection of indicator gases when installed close to the coal fire risk area underground.Furthermore,a field application of the NDIR-based monitoring system in a coal mine shows that the NDIR-based spectrum analyzer has a permissible difference from the chromatography in measuring the concentrations of various indicator gases.Besides,the advantages of high accuracy,quick analysis and excellent security of the NDIR-based monitoring system have promoted its application in many coal mines.

Activation characteristics analysis on concealed fault in the excavating coal roadway based on microseismic monitoring technique

In order to effectively monitor the concealed fault activation process in excavation activities, based on the actual condition of a working face containing faults with high outburst danger in Xin Zhuangzi mine in Huainan, China, we carried out all-side tracking and monitoring on the fault activation process and development trend in excavation activities by establishing a microseismic monitoring system. The results show that excavation activities have a rather great influence on the fault activation. With the working face approaching the fault, the fault activation builds up and the outburst danger increases; when the excavation activities finishes, the fault activation tends to be stable. The number of microseismic events are corresponding to the intensity of fault activation, and the distribution rules of microseismic events can effectively determine the fault occurrence in the mine. Microseismic monitoring technique is accurate in terms of detecting geologic tectonic activities, such as fault activations lying ahead during excavation activities. By utilizing this technique, we can determine outburst danger in excavation activities in time and accordingly take effective countermeasures to prevent and reduce the occurrence of outburst accidents.

Mechanism of gas pressure action during the initial failure of coal containing gas and its application for an outburst inoculation

Faced with the continuous occurrence of coal and gas outburst(hereinafter referred to as“outburst”)disasters,as a main controlling factor in the evolution process of an outburst,for gas pressure,it is still unclear about the phased characteristics of the coupling process with in situ stress,which induce coal damage and instability.Therefore,in the work based on the mining stress paths induced by typical outburst accidents,the gradual and sudden change of three-dimensional stress is taken as the background for the mechanical reconstruction of the disaster process.Then the true triaxial physical experiments are conducted on the damage and instability of coal containing gas under multiple stress paths.Finally,the response characterization between coal damage and gas pressure has been clarified,revealing the mechanism of action of gas pressure during the initial failure of coals.And the main controlling mechanism during the outburst process is elucidated in the coupling process of in situ stress with gas pressure.The results show that during the process of stress loading and unloading,the original gas pressure enters the processes of strengthening and weakening the action ability successively.And the strengthening effect continues to the period of large-scale destruction of coals.The mechanical process of gas pressure during the initial failure of coals can be divided into three stages:the enhancement of strengthening action ability,the decrease of strengthening action ability,and the weakening action ability.The entire process is implemented by changing the dominant action of in situ stress into the dominant action of gas pressure.The failure strength of coals is not only affected by its original mechanical strength,but also by the stress loading and unloading paths,showing a particularly significant effect.Three stages can be divided during outburst inoculation process.That is,firstly,the coals suffer from initial damage through the dominant action of in situ stress with synergy of gas pressure;secondly,the coals with spallation of structural division are generated through the dominant action of gas pressure with synergy of in situ stress,accompanied by further fragmentation;and finally,the fractured coals suffer from fragmentation and pulverization with the gas pressure action.Accordingly,the final broken coals are ejected out with the gas action,initiating an outburst.The research results can provide a new perspective for deepening the understanding of coal and gas outburst mechanism,laying a theoretical foundation for the innovation of outburst prevention and control technologies.

基于PLC与Wincc的井下主煤流监控系统设计

针对孔庄矿井下主煤流系统自动化程度不高的情况,介绍了一套以PLC与Wincc为控制核心的监视控制系统。该系统采用工业以太网通信,除了能够实时监控每台设备,还具有操作记录、运行记录、报表打印等功能。进一步提高了主煤流系统自动化程度。

陕西煤矿冲击地压发生规律与分类防治

随着煤炭资源开采区域不断向西部以及深部转移,西部地区冲击地压矿井数量呈井喷式增长。陕西省作为煤炭大省,煤炭开发供应规模稳居全国前列,但冲击地压灾害尤为突出,为了有效遏制本地区煤矿冲击地压频繁发生势头,并为类似条件矿区冲击地压防治提供借鉴,通过分析陕西煤矿10年来的24座矿井、85起冲击地压案例,基本厘清了冲击地压发生规律,并开展了基于主控因素的分类防治研究。研究结果表明:陕西省煤矿冲击地压具有灾害矿井集中、灾害程度严重、多灾害叠加影响显著、防治难度大等特点;冲击地压监测技术、防治技术与地方法规建设历程几乎同步,达到了起步晚,起点高,示范效应强的结果;基于冲击地压主控因素,将陕西省冲击地压划分为3大类,分别为:坚硬顶板主导型、地质构造主导型和宽煤柱主导型,并针对主控因素提出弱化坚硬顶板、转移煤柱高集中应力、释放构造应力的防治方法。通过10年来的工程实践,不断优化矿井开采设计,探索煤层厚硬顶板千米顺层钻孔区域压裂新技术,加大防冲卸压技术的落实,冲击地压显现逐年减少,成果显著。

新巨龙煤矿煤层大巷冲击地压防治技术

针对新巨龙煤矿3303工作面回采末期开采扰动对煤层大巷产生的冲击地压风险,采用微震监测分析了开采期间工作面超前煤岩体破裂的分布和演变规律,理论分析了大巷保护煤柱区应力分布形态,数值模拟分析了工作面开采前后大巷煤柱区应力分布特征及煤层大巷在工作面采动影响下的应力分布及演变规律,阐述了新巨龙煤层大巷区域冲击地压发生机理。研究表明:大巷保护煤柱区域应力呈“马鞍形”分布,受工作面采动影响,应力与超前支承压力叠加逐渐增大。工作面回采末期,采空区连通范围增大也导致支承压力峰值增大。3303工作面超前支承压力影响范围约为180 m,工作面距大巷小于180 m时,受采动垂直应力影响较明显,巷道帮部冲击风险增强。此外,通过优化3303工作面终采线位置,采取巷道加强支护、巷道煤体卸压及顶板爆破卸压等针对性防治方案,工作面回采末期大巷区域矿震少且能量低,冲击地压防治效果显著。

矿井主排水泵房在线监控系统开发研究

为进一步探究如何提升矿井主排水泵房的监控有效性,在研究中,首先基于工业以太网和PLC技术,对矿井主排水泵房在线监控系统进行整体架构设计;而后应用传感器技术、智能算法等多方面的内容,对该系统的软硬件部分进行详细设计;最后模拟主排水泵房环境对该在线监控系统进行初步测试。测试结果显示,该系统在基本性能和故障识别准确率方面均较优,表明该系统的设计取得了初步成功,有望在今后的工作中得到逐步推广应用。

基于PLC的煤矿主通风机监控系统

详细论述了以PLC为测控核心的系统结构、风机启动控制机制、模拟量测量方法,利用PID模糊控制器实现风量闭环控制,综合采用嵌入式和WWW网络版组态软件形成上位机软件冗余系统。该系统基于企业计算机网络,实现了主通风机运行参数、通风数据的实时监测与风机主辅设备控制的一体化。

矿井瓦斯监测多传感器信息融合模型

分析了矿井瓦斯监测中存在的对传感器的影响因素多等单个传感器本身所不能解决的问题,提出了利用多传感器信息融合技术来增加系统的信息利用率、提高整个系统的精度、可靠性和容错能力的方法。在讨论矿井瓦斯监测的信息源的基础上,确定了瓦斯监测多传感器信息融合的结构模式,利用状态空间方法对此结构模式进行了描述,建立了瓦斯监测系统多传感器信息融合的状态空间模型。采用人工智能方法,建立了多传感器信息融合的模糊神经网络算法模型,实验结果表明,该模型是有效的。

煤矿主排水泵计算机远程监控系统设计

针对煤矿主排水泵的特点和当前测控技术发展,本文介绍了一种基于模块化的煤矿井下主排水系统计算机监控系统。该系统实时采集水泵系统的运行参数自动控制水泵的启、停和切换故障机组,具有语音报警、报表输出及水泵性能测试等功能,对实现煤矿主排水泵的自动化管理具有参考价值。

基于数据挖掘的火电机组主要参数基准值获取方法

采集火电机组重要参数的历史运行数据,基于数据挖掘的方法对参数进行数据清理和数据规约,根据关联规则挖掘历史运行参数的基准值并给定相应的偏差范围。以某300MW机组为例,结合系统中的多重数据验证模块,对获取的基准值和偏差范围进行了试验验证。结果表明,采用数据挖掘手段获取的基准值和偏差带的准确性较高,保障了煤耗在线监测系统的准确性与可靠性,有利于电力调度的合理实施。

煤矿主要通风机远程无线监控系统设计

针对因煤矿主要通风机房位置偏僻且有线网络不易覆盖等造成的主要通风机监控系统易沦为"信息孤岛"的问题,提出了一种基于移动平台的煤矿主要通风机远程无线监控系统设计方案。该系统采用GPRS DTU模块与现场PLC通信,从而获取现场监控数据,并通过GPRS网络将监控数据上传至云端数据服务器;基于Android系统的移动客户端采用Socket通信模式,通过3G、4G或WiFi无线网络接入云端数据服务器,使用户可随时随地远程监控主要通风机运行状况。测试结果验证了该系统的可行性。

基于PLC的煤矿主通风机冗余监控系统设计

煤矿通风机冗余监控是确保煤矿安全生产的重要保障。针对硬件冗余成本高的问题,利用S7-300 PLC设计软冗余监控系统。采用主、备双CPU配置软冗余的Profibus-DP监控系统,由PLC的工作状态确定DP主机,并应用冗余通风机及驱动设备满足DP从站的不间断倒机切换需要。该系统可在线切换故障主机或通风机设备,有效提高煤矿安全生产的可靠性。

PLC计算机远程监控系统在井下主排水泵系统中的应用

结合煤矿井下主排水系统的特点,介绍了一种基于模块化的计算机远程监控系统,并将其应用到煤矿井下主排水系统中。该系统不但能够实现远程监测和控制的目的,还具有语音报警、报表输出等功能,实现了煤矿井下主排水系统的自动化控制。

一种矿井主要通风机故障诊断系统

采用经极限学习机训练的神经网络建立故障诊断模型,基于该模型设计了一种矿井主要通风机故障诊断系统,介绍了该系统的软硬件设计方案。测试结果表明,该系统中极限学习机算法运行时间仅为0.031 3s,故障诊断准确率不低于97.35%,其实时性和准确性优于基于BP神经网络、ELMAN神经网络、经支持向量机训练的神经网络等模型的主要通风机故障诊断系统。

煤矿主提升钢丝绳激光与强磁在线检测技术的研究与应用

煤矿主提升钢丝绳在使用过程中会出现磨损、锈蚀、疲劳及断丝等损伤,是造成主提升系统人员伤亡和设备损失的重大安全隐患。目前国内绝大部分煤矿主提升系统(主井、副井)钢丝绳的检测方法仍停留在眼观、手摸、卡尺量等原始的检测方法,检测误差大、效率低。便携式钢丝绳探伤仪开始逐渐代替人工检测,检测效率明显提高,但因设备使用和操作不便,不能实时监测,并存在辐射危害,未能大面积推广和应用。以平煤股份十三矿副井主提升钢丝绳激光与强磁在线检测系统为例,对主提升系统钢丝绳在线监测技术进行研究与应用分析,为矿井综合自动化建设奠定基础。

新型运输大巷车辆监控系统的研究与应用

所研制的运输大巷车辆监控系统采用先进的RFID自动识别系统,可实时监测运输大巷中车辆的位置;由智能化的信号机执行指令,控制、驱动路口及关键路段红绿指示灯;而传感器、读卡器、信号机、分站之间的数据通信采用CAN现场总线技术。整个巷道的车辆行驶情况及巷道红绿灯状态通过工业环网与全矿自动化系统相连。介绍了该系统的组成、功能及主要技术指标等。