Method for prevention and control of spontaneous combustion of coal seam and its application in mining field

Spontaneous combustion of coal seam has been and continues to be a big problem in coal mines. It could pose great threat to the safety of the whole mine and all miners, especially when it occurs in or nearby coal mines. Besides, environment of area surrounded mines during combustion can be threatened where large amount of toxic gases including CO_2, CO, SO_2 and H_2S can be leased by fire in mine. Hence, it is important and significant for scholars to study the controlling and preventing of the coal seam fire. In this paper, the complicated reasons for the occurrence and development of spontaneous combustion in coal seam are analysed and different models under various air leakage situations are built as well. Based on the model and approximately calculation, the difficulty of fire extinguishment in coal seam is pointed out as the difficulty and poor effect to remove the large amount of heat released. Detailed measurements about backfilling and case analyses are also provided on the basis of the recent ten years' practice of controlling spontaneous combustion in coal seams in China. A technical fire prevention and control method has been concluded as five steps including detection, prevention, sealing, injection and pressure adjustment. However, various backfill materials require different application and environmental factors, so in this paper, analyses and discussion about the effect and engineering application of prevention of spontaneous combustion are provided according to different backfilling technologies and methods. Once the aforementioned fire prevention can be widely applied and regulated in mines, green mining will be achievable concerning mine fire prevention and control.

Combustion mechanism and control approaches of underground coal fires:a review

With the large-scale mining of coal resources,the huge economic losses and environmental problems caused by underground coal fires have become increasingly prominent,and the research on the status quo and response strategies of underground coal fires is of great significance to accelerate the green prevention and control of coal fires,energy conservation and emission reduction.In this paper,we summarized and sorted out the research status of underground coal fires,focused on the theoretical and technical issues such as underground coal fire combustion mechanism,multiphysics coupling effect of coal fire combustion,fire prevention and extinguishing technology for underground coal fires,and beneficial utilization technology,and described the latest research progress of the prevention and control for underground coal fire hazards.Finally,the key research problems in the field of underground coal fire hazards prevention and control were proposed in the direction of the basic theory,technology research,comprehensive management and utilization,with a view to providing ideas and solutions for the management of underground coal fires.

Study and application of plasticity plaster-slurry for preventing coal spontaneous combustion

Introduced the modulation scheme, function and mechanism of plasticity plaster slurry preventing coal spontaneous combustion. The applications show that the plasticity plaster slurry has good hygroscopicity and adsorptivity. To spray it on the coal wall of tunnel can shut off leakage wind fast and effectively. To press it into the coal body can absorb the heat and descend the temperature, surround the coal pieces, eliminate the possibility of the fiery district resuming combustion.

RESEARCH ON RISK OF SPONTANEOUS COMBUSTION IN MINING AREA OF FULLY-MECHANIZED WORKING FACE WITH TOP-COAL DRAWING

Air leakage velocity in intake goaf and distribution of air leakage in mining area are determined by Instantaneous and steady liberation of tracer gas SF6. Gas concentration and temperature in gob are measured and three oxidation areas in goaf are determined. According to oxidation experiment of coal and in-site measurements, the gases of carbon monoxide and dioxide can be produced laraely by coal and oxygen combination at ambient temperature and the temperature of coai and rock In goaf con rise 10℃ due to heat produced by coai and oxygen combination.There is a great risk of spontaneous combustion in neighboring oId gob because of air leakage for pillar mining.

Local dynamic balance theory and technology of flow field in multilayer gob area

Flow field in multilayer gob area, which formed in small hiden-depth, multi-coal layer groups, close distance, hard coal layer, and hard roof, possesses characteristics such as complex, changeable and unstable. Dynamic balance theory of local flow field in multilayer gob area was built based on the realistic requirement that the serious threat on current mining coal layer by large-scale spontaneous combustion fire on close spontaneous combustion coal layer group of Datong Coal mining area at the ＇di-hard＇ conditions was caused by small coal pit mining. The kernel was in dynamic balance between flow field pressures of working face and local flow field in multilayer gob area was kept by transformation. Corresponding technology and set of devices were developed.

New Scheme of Roadway Layout in Longwall Top-Coal Caving System

Based on mining design theory and practice, a production system of stagger-arrangement roadway in thick seams is put forward for the first time. The system can comprehensively solve the problems in longwall top-coal caving system, such as raising recovery ratio, discharging gas, preventing spontaneous combustion and improving the upkeep of roadway etc.

A novel coating technology for fast sealing of air leakage in underground coal mines

Air leakage in underground coal mines presents a serious hazard for coal production and the safety of miners.Coating technology is commonly used as an efficient means for preventing air leakage.To address existing problems with high dust concentrations in large operations involving complex processes and the high cost of traditional coating technology,a novel coating technology that ensures intrinsic safety by utilizing water pressure and wind pressure was developed.This new coating technology was designed to suction and spray,and the technical parameters of its spray performance was also studied.The experimental tests and evaluation indicated the optimum working range is 0.3–0.7 MPa of wind pressure,1.2–10.2 L/min of water quantity,and 1.0–3.5 m of spraying distance.Moreover,this novel coating technology was tested in the Dashuitou Coal Mine in Gansu Province of China.Compared with conventional counterparts,the proposed new technology is safe,efficient,and convenient to operate.During spraying,dust concentrations were kept at less than 10 mg/m3,and the average rebound ratio resilient rate of solid materials was below 13%.After spraying,the average leakage every 100 m was 4 m3/min,and the oxygen volume fraction in the adjacent goaf was approximately 4%,demonstrating excellent air leakage prevention.

煤矸石自燃的关键影响因素及治理方法研究现状

煤矸石作为煤炭的伴生产物,长期堆存过程中自燃现象频发,直接或间接产生生态污染、水体污染、地质灾害等诸多问题,造成巨大经济损失和人员伤亡。煤矸石从堆积初期到燃烧状态受诸多因素影响,包括自身性质、自燃条件和外部环境等,是一个复杂的物理化学反应过程。为提高煤矿矿区矸石自燃的防治能力,分析了煤矸石自燃理论的研究现状,系统总结了现阶段国内外学者对煤矸石自燃机理和治理方法的研究进展。围绕可燃物、氧气、温度3个影响煤矸石自燃的必要因素,提出了引发自燃的主要关键影响因素和作用过程机理。较全面介绍已有煤矸石山自燃防治的主要方法,对比分析了各种常规煤矸石自燃灭火手段以及治理技术的优缺点,指出了常规简单技术治理效果的局限性。针对煤矸石作为砂、石等替代材料,回填露天矿坑、采煤塌陷区等区域进行土地整治和生态修复,提出在防治过程中要明确自燃治理的控制对象,提升防灭火材料的特定性能,通过智能化设备提高辨识准确性进行精细化监控,并运用多种监测预警技术协同自燃防治材料多手段多方法运用综合治理,并提出了煤矸石自燃防治技术的未来发展和矿用防灭火材料的研究方向,为后续开展煤矸石自燃机理研究及自燃防治工程应用提供参考和理论支持。

煤矿热动力灾害防控研究现状及趋势综述

为分析煤矿热动力灾害防治理论及技术相关研究现状,提高对煤自燃、瓦斯爆炸及诱发耦合灾害等方面的认识,系统总结了当前煤矿热动力灾害研究的成果,分析研究领域国内外进展及不足。研究结果表明:当前热动力灾害基础理论方面需深入多灾种耦合复杂致灾机理及影响机制的研究,防治技术方面需着力发展精细化、低碳化、智能化防治技术及装备,管理方面需以科学理论为基础,制定合理可行的监管监察防灾治灾临界指标。研究结论为煤矿热动力灾害防治理论及技术进一步发展提供参考。

矿井带式输送机火灾烟流特性及其预警防控综述

为有效防控煤矿井下带式输送机火灾事故,保障煤矿工作人员的生命财产安全,系统分析矿井带式输送机火灾的起火原因、燃烧特性、烟流特性、监测预警技术及防治措施,并基于当前研究现状提出展望。结果表明:引发带式输送机火灾的主要原因是摩擦温升、电气设备故障及明火;研究带式输送机火灾燃烧和烟流特性采用的巷道火灾模型及数值模拟相关参数具有一定局限性,需综合考虑运输巷道实际工况及环境等参数;国内虽有针对带式输送机火灾的监测预警系统,但其尚有不足,需引入5G、大数据及人工智能等新兴技术予以完善,并结合硬件探测及人员管理等方面,健全煤矿带式输送机火灾防治体系,进而全面推动煤矿安全智能化建设。

地下煤火分维—分级探测预警技术研究

为实现煤自燃隐蔽火源的高效监测预警和防治,本文对地下煤火分维—分级探测预警技术展开研究。首先,揭示煤自燃受热升温及燃烧过程的煤自燃的电磁—声波—温—气变化特征,形成电磁—声波—氡气—红外多维探测方法,实现井上井下联合多维探测应用;其次,根据大尺寸煤自燃指标气体产生规律,建立基于正压输运的煤自燃监测预警体系,实现地下煤自燃发火的分级精准预警;最后,依据复杂区域综放面煤层自燃发火特点、影响因素及变化规律,提出复杂开采煤自燃灾害综合防治技术体系。研究成果可为井下煤自燃灾害预警防治提供依据与参考。

煤制油气化灰渣防灭火凝胶的制备及性能

针对煤制油气化灰渣堆积造成环境污染和固废资源浪费等问题,本研究提出以气化灰渣为基料、羟丙基甲基纤维素(HPMC)为胶凝剂,制备气化灰渣凝胶煤矿防灭火材料,使用扫描电镜和傅里叶红外光谱仪分析其微观形貌与表面官能团特征。考察了材料的胶凝时间、热稳定性及保水性,确定了气化渣凝胶最优配方为水灰比1∶1.25、HPMC添加量1.5%(质量分数)。该凝胶较好抑制了煤自燃过程中羟基、甲基、亚甲基、取代芳烃、醚碳氧键等官能团反应,与未经凝胶处理的煤样相比,经凝胶处理的煤样在80℃时芳香烃峰面积减小11.85%,脂肪烃峰面积减小43.07%,120℃时芳香烃峰面积减小27.36%,脂肪烃峰面积减小44.23%。凝胶处理的煤样在氧化升温过程中,100℃时CO浓度降低65.07%,200℃时CO浓度降低53.09%,C 2H 4浓度降低23.68%。微观和宏观结果表明,气化灰渣凝胶较好地抑制了煤自燃进程,阻化性能优于CaCl 2,可有效防治煤自燃灾害,解决灰渣堆积问题,实现固废资源化利用。

社会风险预警与防控机制建设:一个社会燃烧理论的框架

社会风险治理面临治理观念困境、多元格局困境、社会参与困境。社会燃烧理论为解释社会治安风险的形成及防控提供了有效的逻辑支撑。依据社会燃烧理论,社会治安风险的形成需经历积累与萌芽、发展与升级、爆发与燃烧、平息与善后阶段。多重因素导致的社会矛盾是“可燃物”,失范的舆论是“助燃剂”,缺位的治理行为是“着火点”。完善社会风险治理,可从减少燃烧因子、控制助燃物质、降低社会温度三个层面着手,做好源头治理,建立常设性的预警机制,形成多元共治的协同治理局面。

残煤复采区巷道掘进凝胶堵漏防灭火技术研究

采空区中遗留煤炭自燃现象直接影响着煤矿的安全高效开采,而采用堵漏材料封闭漏风通道是解决采空区煤自燃问题的有效方法。以运河煤矿F1301复采工作面为工程背景,针对在采空区中掘进巷道时遗留松散煤体的自燃隐患问题,制定了松散煤体凝胶堵漏防灭火技术实施方案,采用COMSOL数值模拟方法研究了不同注胶时间与压力下的凝胶扩散规律,并进行了工程应用。结果表明:注胶时间和压力与凝胶扩散范围成正比,综合考虑注胶效果与成本,选取10 MPa、140~160 min为最佳的注胶压力与时间,注胶钻孔间距设置为5 m;实施凝胶堵漏防灭火方案后,巷道两侧观测钻孔监测数据显示,标志气体CO体积分数稳定于24×10^(-6)以下,凝胶堵漏防灭火效果良好,有效消除了采空区遗留煤炭自然发火隐患。

矿井煤自燃灾害监测预警技术及发展趋势

以降低矿井火灾的发生率为目标,梳理了矿井煤自燃灾害现有监测预警技术的发展现状,总结了现有技术的局限性和不足,指出未来发展应注重先进监测技术的应用、预测技术准确性的提升、预警系统和智能化管理的发展等。针对矿井煤自燃灾害隐蔽性、持续性、扩散性和难以控制的特点,提出矿井煤自燃灾害监测预警技术未来发展方向:提升煤自然发火临界值确定方法的综合性,利用新兴设备和先进技术完善煤自然发火临界值的确定方法;针对矿井煤自燃复杂环境,可通过研究声波探测等新型先进技术手段,提高矿井煤自燃监测参数的全面性和精细化;推动矿井煤自燃监测预警技术的创新性和决策的智能化,利用数字孪生技术提供精准的模拟与预测能力、优化防控方案、提供培训和应急管理以及数据分析和决策支持等方面的帮助;聚焦矿井自燃灾害全面感知、精准预测与防控智能一体化建设,加强对矿井自燃灾害数据分析、灾前主动预警、灾后事故治理、火区自动封闭等技术的研究。

大倾角工作面采空区均压-注氮联合防火数值模拟研究

以峻德煤矿93172大倾角外部漏风工作面为例,研究大倾角外部漏风采空区均压参数合理性以及对注氮防火的影响。采用Fluent数值模拟方法对采空区进行流场分析,充分考虑位压的影响,合理设置工作面和采空区进回风口及漏风口压力边界参数;建立了“L”形大倾角采空区冒落分布模型,进行采空区“恰当均压”,“欠均压”,“过均压”数值模拟,探究不同均压工况的采空区自燃三带分布,同时探讨了采空区均压注氮的合理参数选择。结果表明:“恰当均压”的采空区自然氧化带宽度最短;注氮防火应在“恰当均压”条件下进行,否则将会极大降低采空区惰化效果,徒增注氮量。研究结果对现场科学制定均压-注氮联合防火措施提供理论指导,同时压力边界参数设置方法为大倾角工作面采空区均压-注氮联合防火相关数值模拟研究提供科学参考。

高校实验室自制气体燃烧装置风险防控研究

高校实验室自制气体燃烧装置存在较高风险。首先介绍了计算可燃混合气爆炸极限、绘制燃烧三元相图两种方法,用于判断常压室温条件下混合气体燃爆特性。然后以常压燃烧器和爆燃/爆轰装置为例研究爆炸风险,分析了装置冲击部位异常温升的关键因素,给出了负压状态下预混可燃气发生绝热压缩导致爆炸的计算实例。最后,基于本质安全,从实验方案安全技术要点、实验装置设计制造安全要求、实验室环境安全提升、个人防护用品配置四方面提出爆炸防控措施。

改性固废基多孔颗粒吸附CO_(2)及其解吸抑制煤自燃特性研究

煤矿采空区遗煤自燃灾害频发,严重危害矿井安全生产。为了防治采空区遗煤自燃,本文研究了一种胺改性固废多孔材料,并研究了胺改性固废多孔材料的CO_(2)吸附性能及抑制煤自燃特性。研究结果表明,有机胺改性剂能够成功负载在固废多孔颗粒上,并且在不同有机胺(乙醇胺(MEA)、二乙烯三胺(DETA)、四乙烯五胺(TEPA)、聚乙烯亚胺(PEI))改性多孔颗粒中,四乙烯五胺(TEPA)改性多孔颗粒CO_(2)吸附性能最好。CO_(2)吸附实验结果表明,随着改性剂负载量的增大,CO_(2)吸附量先升高后降低,25℃、1bar条件下,有机胺负载量为20wt%时,吸附量最大达到119.24mg/g;改性剂负载量相同时,CO_(2)吸附量随着温度的升高先增加后降低,70℃时吸附量最高,为128.97 mg/g。程序升温测试结果显示,相较于添加未吸附CO_(2)的改性颗粒,添加吸附CO_(2)的改性颗粒后,煤样的交叉点温度升高了29.2℃,有效降低了煤自燃危险性,温度升高过程中改性颗粒吸附的CO_(2)能够解吸,降低煤颗粒周围的氧浓度,从而抑制采空区遗煤自燃。本文研究对促进工业固废的高效利用、推动采空区煤自燃灾害高效防控技术的发展具有重要意义。

A^(l3+)交联的聚丙烯酸钠凝胶防灭火特性

为解决传统矿用防灭火凝胶保水性能差、受热易分解等问题,基于高分子材料聚丙烯酸钠易与高价态金属离子发生分子交联从而凝胶化的特性,研制出一种耐高温、高保水的新型Al^(3+)聚合物防灭火凝胶。从热稳定性、阻化效果及官能团3个方面分析Al^(3+)聚合物凝胶的阻化机理,首先利用恒温干燥箱和热重试验测试凝胶在不同温度条件下失水率、质量及特征温度点变化情况;其次利用程序升温气相色谱法对升温过程中的气相产物进行检测,根据检测结果进行气体阻化率计算和活化能氧化动力学分析;最后利用红外光谱仪研究聚合物凝胶对煤分子中官能团的影响。结果表明:Al^(3+)与聚丙烯酸钠交联形成的三维网络结构使凝胶具有良好的热稳定性,在150℃恒温条件下加热12 h,最大失水率为42.9%,凝胶阻化煤样其特征温度点均出现不同程度的延后;凝胶阻化后的煤样CO气体的生成量大幅度减少,最大CO阻化率为76.76%;凝胶能通过提高煤氧反应所需的活化能以及降低参与煤氧反应官能团的含量来降低煤的自燃倾向性,活化能最大增幅为14.6%。研究结果以期为高分子材料在煤火灾害治理方面的应用及发展提供一定的参考。

高阳煤矿矸石山生态修复治理

高阳煤矿矸石场C区域存在坡面矸石自燃、堆体堆存不稳定、堆场环境污染等问题。结合现场情况提出以注浆为主、覆土为辅的防灭火技术,提出采用坡体整形、矸石场截排水、矸石场覆土措施,解决堆体不稳、雨水对坡面的冲刷等问题,并为后续植被种植等创造良好条件。现场应用后,矸石场C区域自燃、环境污染严重等问题得以较好解决,采取的生态恢复治理措施应用效果显著。