Atmospheric disturbance on the gas explosion in closed fire zone

In order to avoid serious safety accidents caused by closed fire zone,based on the continuous monitoring of atmospheric pressure at different monitoring points in multiple mines,the atmospheric pressure fluctuation model and the air leakage model were established and analyzed.The change law with time of oxygen concentration and gas concentration in the fire zone were obtained due to atmospheric disturbances under the influence of different pressure difference,volume and size of fire area,wind resistance,gas emission,sealing moments,etc.so as to evaluate the explosion risk of a closed fire zone.Research showed that the mine atmosphere fluctuates with the atmosphere of ground,and the pressure difference between the inner and outer sides of the enclosed fire zone is affected by the periodic fluctuation of atmosphere,which has about 16-h cosine fluctuation and approximate 8-h fixed value.Compared with the fire zone with poor sealing quality,good sealing fire zone has better resistance to atmospheric disturbance.The reduction of oxygen concentration in the inner side of a well-sealed fire zone mainly depends on the dilution of methane,which is more likely to accumulate and rise rapidly.And the fire zone with poor sealing quality is easy to be interfered.The inner oxygen concentration and gas concentration are easily affected by the absolute gas emission and the air leakage in the fire zone.Fire zone with small wind resistance and small volume is especially obvious.At the initial stage of the closed fire zone it's very possible to happen explosion.The time duration of explosion danger varies under different conditions,and the atmospheric disturbance may lead to repeated explosions in some cases.It's suggested to take some methods to avoid explosions according to the real-time situation,closure time,oxygen concentration and gas concentration of fire zone.

Rules of variation in hydrogen during reignition of underground fire zones of spontaneous coal combustion

In light of the possibility of reignition when unsealing the closed fire zones, the occurrence of reignition was simulated by a home-made experimental device, hydrogen variety rule from combustion to unsealing was analyzed, the three-stage generation model of hydrogen during reignition in fire zone was put forward and the probability that hydrogen was taken as an indicator gas was discussed. The results show that: when fire zone is ready to unseal, which is filled with hydrogen at a high concentration, it is more prone to reignite.

Theoretical analysis and applications of Y-Inversion Ventilation System in a mine fire zone

Based on mine fire fighting practices at the 1110 working face of the Brapukuria Coal Mine,Bangladesh,we introduce and discuss the Y-Inversion Ventilation System,the latest technology used both in mine fire zone management and the unsealing process.This ventilation system can ensure that all miners breathed fresh air,providing protection for them during fire fighting and unsealing the fire zone.On the other hand,adjusting the amount of air at the working face and forming a CO leakage path controlled the state of the fire and as well ensured that the different fire extinguishing measures could be applied successfully.These are all fundamental techniques which ensured successful fire extinguishing and unsealing of the fire zone.We also analyzed the main reasons for the spontaneous coal combustion that occurred at the 1110 working face.Successful application of advanced composite polymer colloidal perfusion techniques,polymer foam MEA perfusion and fire-prevention technology by infusing nitrogen,used in mine fire zone management and unsealing,are presented.We value the experience with these techniques very highly and are of the opinion that these techniques could be widely used in mine fire fighting practices under similar spontaneous coal combustion conditions elsewhere.

Building fire zone model with symbolic mathematics

To apply the fire modelling for the fire engineer with symbolic mathematics,the key equations of a zone model were demonstrated. There were thirteen variables with nine constraints,so only four ordinary differential equations (ODEs) were required to solve. A typical fire modelling with two-room structure was studied. Accordingly,the source terms included in the ODEs were simplified and modelled,and the fourth Runge-Kutta method was used to solve the ordinary differential equations (ODEs) with symbolic mathematics. Then a zone model could be used with symbolic mathematics. It is proposed that symbolic mathematics is possible for use by fire engineer.

RS AND GIS-BASED FOREST FIRE RISK ZONE MAPPING IN DA HINGGAN MOUNTAINS

The Da Hinggan Mountains is one of the most important forest areas in China, but forest fire there is also of high frequency. So it is completely necessary to map forest fire risk zones in order to effectively manage and protect the forest resources. Two forest farms of Tuqiang Forest Bureau (53°34′-52°15′N,124°05′-122°18′E) were chosen as typical areas in this study. Remote sensing (RS) and Geographic Information System (GIS) play a vital role and can be used effectively to obtain and combine different forest-fire-causing factors for demarcating the forest fire risk zone map. Forest fire risk zones were described by assigning subjective weights to the classes of all the coverage layers according to their sensitivity to fire, using the ARC/INFO GIS software. Four classes of forest fire risk ranging from low to extremely high were generated automatically in ARC/INFO. The results showed that about 60.33% of the study area were predicted to be upper moderate risk zones, indicating that the forest fire management task in this area is super onerous. The RS and GIS-based forest fire risk model of the study area was found to be highly compatible with the actual fire-affected sites in 1987. Therefore the forest fire risk zone map can be used for guidance of forest fire management, and as basis for fire prevention strategies.

不同草原防火政策下内蒙古草原火灾发生风险及其驱动因素的研究

草原火灾是草原生态系统中重要的干扰因子之一,不同时期的草原防火政策可能会导致草原火灾发生概率及驱动因素发生变化。本研究基于内蒙古1981~2020年草原火灾数据,以新旧《草原防火条例》实施时间(旧《草原防火条例》1993年10月5日颁布并实施,新《草原防火条例》2008年11月19日颁布并于2009年1月1日起实施)为界线,通过随机森林模型分4个时期(1981~2020年、1981~1993年、1994~2008年、2009~2020年)对内蒙古草原火灾发生概率与驱动因素进行比较与分析,并绘制草原火灾风险等级区划图。结果表明:(1)4个时期建模的全样本AUC在0.930~0.940之间,精度优异。(2)在不同时期,气象因素(日平均相对湿度、气温日较差等)始终是影响草原火灾的主导因素,海拔、距火点最近公路距离等因素也是内蒙古草原火灾发生的重要驱动因素;(3)1981~1993年和1981~2020年草原火灾风险区基本相似,中、高、极高草原火灾风险区主要集中在呼伦贝尔市大部分地区和兴安盟北部,1994~2008年中、高、极高草原火灾风险区主要集中在呼伦贝尔市,而2009~2020年中、高、极高草原火灾风险区主要集中在呼伦贝尔市西部、锡林郭勒盟北部、阿拉善盟东南部、乌海市和鄂尔多斯市东部。

水电工程主厂房防火防烟分区划分的探讨

鉴于《水电工程设计防火规范》修编过程中,对主厂房防火分区、防烟分区和疏散距离存在不同认识,本文从防火设计的基本理念出发,分析了水电工程的特殊性,同时采用性能化设计数模理论,确定了规范中防火分区、防烟分区面积,以及疏散通道长度的依据,探讨了水电工程的特点,为特殊工程防火设计规范编制提供参考。

近距离煤层群联合开采火区“三位一体”治理技术

针对近距离煤层群开采期间的自然发火防治难题,以新维煤矿2110、3108工作面断层区域火点处置为例,通过实验研究与现场实践相结合的手段,开展隐蔽火点的探测与综合治理技术研究。3号煤层自然发火模拟实验结果表明:CO、C_(2)H_(4)体积分数与煤温呈二次函数关系,可用于煤层自然发火预测预报;氧气体积分数的降低可以有效抑制煤自燃氧化进程,氧气体积分数为7%时最为明显,因此将其设为3号煤层自然发火的临界氧气体积分数。通过自燃隐患分析结合钻孔探查划定了3110轨道巷以西长80 m、宽10 m的F9断层区域为自然发火隐患区域,并提出以注浆降温为先导,以注胶堵漏为核心,以注氮阻爆为手段的液-胶-气“三位一体”的火区治理思路,累计向隐患区域注浆180 t、注胶504 m^(3),2110工作面采空区注氮流量保持在810 m^(3)/h,实现了火区的有效治理,保障了2个工作面的顺利启封与安全回采。

深汕特别合作区火灾风险及消防安全对策措施

为全面提升深汕特别合作区城市与乡村消防安全水平,推动其成为“区域协调发展示范区”,本文结合深汕特别合作区火灾风险防控要求与消防安全管理现状,从老旧建筑、自建房民宿、建筑施工工地和新能源汽车产业等方面进行火灾风险分析,并有针对性地提出落实消防安全责任、聚焦新能源汽车产业消防安全管理难题、推动消防安全检查与火灾隐患整改、加强消防安全宣传教育和培训、落实基层消防安全网格化管理等5项对策措施。

储罐火灾沸溢现象及其控制技术研究进展综述

为更加深入了解储罐火灾沸溢机理及其相应控制技术,通过系统的文献调查,从沸溢现象的研究进展和沸溢现象的控制技术2方面进行分析,从热区机理研究历程、沸溢影响因素等方面对沸溢现象进行归纳,并且从消防控制技术、油面覆盖控制技术等角度出发对沸溢抑制措施进行阐述。研究结果表明:沸溢现象涉及多因素之间的相互关联,热区形成机理是沸溢机理研究的关键点之一,可视化研究能较为直观呈现油品的对流换热行为,进而丰富热区理论;沸溢现象的影响因素较多,沸溢时间预测模型主要是基于初始油层厚度和储罐直径进行拟合、基于经典热波理论和油品本身性质加以修正,其公式适用性较低,对沸溢现象的认识有待加深;沸溢控制技术需进一步完善,目前主要通过阻止全液面火灾发生来间接抑制沸溢,采用油面覆盖等方法直接抑制沸溢的措施仍不够成熟;持续改进沸溢相关的研究模型、补充大尺度实验研究、研发新型覆盖材料、完善消防技战术等是沸溢现象及其控制技术的主要研究方向和发展趋势。研究结果可为深入认识沸溢现象、发展其控制技术、提高相关人员储罐灭火救援能力提供一定参考。

国家速滑馆帘布式防火分隔施工技术应用

在建筑消防工程中,防火分隔技术分为垂直分隔技术和水平防火分隔技术两类。防火分隔的材料一般为二次结构墙、轻钢龙骨防火墙。传统的防火分隔材料为刚性材料,在复杂空间、管道密集处等部位防火分隔施工难度大,施工效果差,很难满足建筑消防要求。近年来,防火帘布作为防火分隔的材料已应用在大型场馆、商场,可以满足复杂部位的防火分隔施工。以异形结构体育馆比赛大厅与观众大厅的防火分隔为例,研究如何设计和施工才能满足该区域防火分隔的施工质量,同时对大型体育场馆、商场防火分隔设计和施工提供了新的解决思路和方法,具有先进性、创新性和极高的推广价值。

国家速滑馆防火复合型静压箱技术应用

在异形高大空间建筑中,采用结构复杂静压箱送风的工程并不多,也没有对静压箱的设计施工颁布相应的设计规范和施工标准,但静压箱设计的优劣直接决定静压箱周围的管线排布和相关房间的净高,以及舒适性和空气质量,因此有必要在实际工程中对静压箱的设计及施工情况进行研究。以国家速滑馆为例,研究异形结构部位静压箱的设计和施工,以满足该工程中对固定看台下方异形静压箱的技术参数要求,确保使用功能,方便施工。

城市轨道交通地下车站防火设计要点研究

以地下车站建筑为研究对象,针对其特殊的地理位置和复杂的的人员流动特点,探讨了地下车站建筑防火设计的关键技术问题。本文对地下车站建筑防火设计的原则进行了阐述,接着对防火分区分级、防火隔离、消防设施、疏散通道等方面的设计要点进行了深入研究。

JSG6束管监测系统优化及应用

为预测采空区遗煤自然发火情况,在12403工作面安装JSG6矿井火灾束管监测系统为矿井防灭火工作提供依据。该系统在应用过程中出现探头位置过低、缺乏保护、束管进水、漏气难以检测、阻力过大等问题,根据实际情况,对核心部件铺设位置进行优化,并设计采样探头保护装置、正压发烟法束管检漏装置、U形气水自动分离装置和双泵采气装置,为监测系统正常运转和检修提供便利。根据束管监测结果,对12403工作面采空区自燃“三带”进行划分,其回风侧散热带和氧化带发育范围分别为0~18.3 m和18.3~67.4 m,根据采空区自燃“三带”的划分,结合束管监测结果可以对采空区重点区域采取有针对性的措施,确保矿井防灭火安全。

重庆市高新区生物防火林带空间布局与规划

重庆市高新区为森林火灾多发地区,为预防和控制森林火灾的发生蔓延、降低火灾造成的损失,以重庆市高新区缙云山和中梁山为研究区域,遵循“因险设防、重点突出、全面规划”的原则,综合考虑阻隔网密度、控制面积、林带有效宽度、林带位置等参数,对高新区的生物防火林带阻隔网进行了规划。为保证防火效果,研究区需新建防火阻隔林带79.18 km。如此,不仅能够达到相关技术标准的要求,而且建设成本可控。

特厚煤层重复采动作用下采空区自燃“三带”位移变化

为探究特厚煤层重复采动下采空区煤自燃“三带”的分布特征,基于束管监测系统,在铜川下石节煤矿222工作面进行现场实测,确定其自燃“三带”的分布规律。借助Fluent软件分别模拟重复采动及单一采动时采空区内氧气浓度的动态分布规律,发现重复采动采空区内实测结果与数值模拟结果基本一致。与单一采动模拟结果对比,重复采动导致采空区内部的散热带和氧化带出现缩短趋势;在进风侧散热带前移6.8%,氧化带前移7.0%;回风侧散热带前移14.3%,氧化带前移11.3%。研究成果能够为重复采动作用下采空区煤自燃危险区域防治提供依据。

南宁市森林火灾风险评估与区划研究

以森林火灾风险评估技术体系为框架,利用南宁市森林火灾风险要素数据对南宁市森林火灾危险性、综合风险、减灾能力和防治区划进行了研究。结果表明:南宁市危险性指数在0.0022~0.2397;综合风险指数在1.0400~3.0000,危险性和综合风险等级高的乡镇主要集中在环大明山及市、县交界处等森林资源丰富、地形地势较为复杂、人类活动较为频繁的区域;南宁市减灾能力指数在0.1220~0.6110,减灾能力等级较高的乡镇多分布在国有林场涉及区域及经济发展较好的城区。在南宁市综合风险与减灾能力基础上,综合考虑南宁市防火工作实际与生态区位,共划分了7个防治区划。评估与区划结果符合南宁市客观实际,能够为南宁市的森林防火决策部署提供参考建议。未来可通过及时更新森林火灾风险要素数据,结合气象等实时数据,进行动态风险评估,为不同时期的森林火灾防控提供更精细化的管理建议。

刍议多压力区管网平差中的消防水量参数选择

文章以南京江北新区南钢生活区供水改造工程为例,在说明了本项目中的多压力区管网平差分析与供水分区设计要点的基础上,从需水量计算、分区供水消防用水量的确定这两方面入手,探讨了多压力区管网平差消防用水量的确定。参考现行标准以及最不利工况条件下消防安全的保持要求,确定出本项目的消防用水量设计要求,即无论是对于低区还是高区,均要求依照同时发生火灾2次、一次灭火用水量为25L/s的要求进行对消防用水量的设计。

永智煤矿5101工作面采空区自燃“三带”范围研究

采空区自燃“三带”范围的确定是矿井防灭火工作的关键。文章以O_(2)体积分数划分法为依据对永智煤矿5101工作面“三带”进行了实测研究,并利用Fluent模拟了漏风风速和O_(2)体积分数分布规律。结果表明:进风巷侧散热带范围为0~19.6 m,氧化带为19.6~68.2 m,窒息带在68.2 m之后。回风巷侧散热带范围为0~10.3 m,氧化带为10.3~36.3 m,窒息带在36.3 m之后;O_(2)体积分数与采空区深度符合二次函数规律;数值模拟与现场实测结果基本相同。最后,计算出采空区工作面安全推进速度为1.47 m/d.

大采高综采工作面防灭火技术优化及效果分析

为优化杭来湾煤矿30201工作面防灭火技术,解决上隅角CO超限问题,结合大采高工作面特点分析CO超限原因,利用预埋束管观测和数值模拟相结合的方法判定采空区煤自燃危险区域,提出工作面防灭火技术优化方案,并对优化效果进行研究分析。结果表明,采空区煤自燃危险区域为氧化带范围,回风侧氧化带距工作面14~140 m,进风侧氧化带距工作面280~410 m;工作面防灭火技术优化后,回风侧氧化带距工作面5~85 m,进风侧氧化带距工作面210~285 m,氧化带宽度缩短约60 m,窒息带明显前移,表明防灭火技术优化有效。