煤矿火灾控制的最近发展和实践外文文献翻译

英文原文Recent Developments and Practices to Control Fire in Undergound Coal MinesS. K. Ray* and R. P. Singh, Central Mining Research Institute, Barwa Road,Dhanbad, Jharkhand 826 001, IndiaAbstract: Coal mine res cause serious threat to the property and human lives. Out-break of re may be dealt with advanced re suppression techniques like Infusion of inert gases or liquid nitrogen, Dynamic Balancing of pressure, Reversal of under-ground mine ventilation, Application of nitrogen foam, Inertisation of Goaf, Water mist etc. The paper addresses all those control techniques in detail. Success story of controlling res in coal mines of different parts of the world are reported. Results of a recently completed Science & Technology (S&T) project with regard to various re suppression techniques like Infusion of liquid nitrogen, Injection of high pressure high stability nitrogen foam, and Water mist on open re are also discussed.Keywords: coal mine re, reversal of underground mine ventilation, nitrogen foam, inertisation of goaf & water mist1. IntroductionSince inception, mining is considered as a most hazardous and dangerous of peacetime activities. An outbreak of re in the underground workings of a mine poses a direct threat from the re itself. Further, an invisible and immediate threat from carbon monoxide poisoning and an explosion, particularly in gassy coal mines is also there. It affects to both persons working underground at the time of the outbreak and to those involved in the subsequent rescue and re ghting. It hampers the coal production and sometimes loss of coal winning machinery. Fires in coal mines may be categorised into two groups viz.,(a) res resulting from spontaneous combustion of coal (b) open res, which are accidental in nature, caused as a result of ignition of combustible materials.In coal mines, res are generally caused due to several reasons viz., sluggish ventilation, high pressure difference across intake and return airways, loose and fallen coal in the goaf area, electricity, mechanical friction, blasting, welding, explosions and illicit distillation of liquor.2. Mine Fire Model Gallery To understand the complex dynamic phenomenon of open res (res that occur in mine airways usually commence from a single point of ignition) and to study the effectiveness of various re suppression techniques viz., liquid nitrogen, high pressure high stability nitrogen foam and water mist, recently Central Mining Research Institute, Dhanbad, India has designed and constructed a Mine Fire Model Gallery. The model gallery is 65.5 m long; arch in shape with a base of 2.4 m and crown height of 2.7 m. The cross section of the gallery is 5.86 m2. The gallery is divided into ring and non-ring zones. An exhaust type axial ow fan having a capacity to deal with 25 m3/s. of air quantity at 50-mm wg pressure has been installed at its end. The gallery is provided with two sliding doors for quick sealing of the re and a rolling shutter for regulation of desired airow. An isometric view of mine re model gallery is shown in Figure 1.It is equipped with a state-of-the-art computer aided on-line telemonitoring system. The system consists of 130 sensors (98 temperature, 25 gas, 3 pressure, 2 heat ux, 1 each velocity and Suspended Particulate Matter (SPM) concentration sensor) and instruments with data logger, computer, computer peripheral etc. for continuous monitoring of various re parameters like gas concentration (O2, CO2, CO, CH4 & H2), air velocity, pressure across re zone and fan pressure, temperature, heat ux, dust and particulate matter concentration inside the gallery.Figure 1 Isometric view of mine re model galleryDetails of the construction of the gallery and its instrumentation system have beendescribed elsewhere In the experiments inner side of the ring zone of the gallery which is 22 m in length (ring zone starts from 10.5 m from the entry of the gallery) was lined with a thin layer of coal slabs, 810 cm thick, brought from Dobrana seam of New Kenda Colliery. Fixing of coal slabs were effected with a mixture of air setting cement and liquid binder. In each set of experiments about 1820 tons of coalswere used.The paper addresses all the above control measures that have been applied all over the world. Results of experimentation on open res in Mine Fire Model Gallery are also discussed.3.Fghting Mine Fires3.1 High Pressure FoamUse of foam plugs has been successful in ghting mine res in roadways where direct attack with water is not possible. USBM studies reveals that the water content of the foam should not be less than 0.20 kg/m3 otherwise the foam is not capable of controlling the re. With sucient ventilating forces (around 8 cm wg) properly generated foam may be transported over 300 m. Foam does not appear to be effective against deep seated, rapidly advancing, buried or dead end res.In India, suppression of spontaneous heating by high pressure high stability foam is a new and effective method. However, the method has been widely used in Czech mines in controlling spontaneous heating of the mined out areas of longwall panels.The foam is produced by high pressure foam generator under the pressure of 10 foaming gas. The produced foam is transported by pipelines or re hoses to the re area. Inert gas (N2, CO2), compressed air or a combination of both is used as foaming gas. The foam generator consists of two independent units namely pumping unit and foam generating unit. The foam is produced from a mixture consisting of water and 5% foaming agent. This mixture is pumped by a pumping unit into a foam-generating unit where the foam is produced . At the same time inert gas (N2) is supplied to the foam-generating unit at a minimum pressure of 0.2 MPa, mixed with foaming mixture sprayed from nozzles and then passes through a ne mesh installed inside the foam generation unit. At the outlet of the foaming unit a re resistant hosepipe of suitable diameter is attached by which the foam is transported to the place of infusion. A schematic diagram for HPHS nitrogen foam generation system is shown in Figure 3.The foam helps in controlling the spontaneous heating in following manner. Reducing air leakage through mined out area Reducing temperature Reducing the rate of sorption of oxygen by the coal as the foam forms a thinprotective lm over the coal. Pumping Unit400 V, 50 Hz5%mixture Fire Hose Foam to FireAffected Areaof water &foaming agent Foam Generating Unit Figure 3 Set up for injection of high-pressure high stability nitrogenHigh pressure nitrogen foam has recently been used in AW1 longwall panel of 1 & 2 Incline mine of Jhanjra project, ECL with very encouraging results. In this mine foam was injected in the longwall goaf through boreholes. A trolley mounted PSA type nitrogen generator having a capacity of 300 Nm3/h. was used. High pressure high stability nitrogen foam (HPHS) is cheap (one kg of foaming agent capable of producing 2 m3 of foam costing about 2.1 $) and has long self life. The HPHS nitrogen foam at a rate of 200 m3/h has been applied during experimentation in CMRI Mine Fire Model Gallery to control open re.The following points are worth mentioning.It has been observed from the results that there was substantial reduction in temperature. The average value of this reduction in temperature has been found to be 207C per hour.After infusion of foam in open re condition the concentration of all the Products of Combustion (POC) like CO2, CO, CH4 and H2 has decreased, indicating the retardation of combustion process.On infusion of foam, reduction of generation rate of CO2 and CO is estimated as 80% and 85%, respectively.High-pressure high stability nitrogen foam technology proved to be promising to control open res. However, 200-m3/h infusion rate was found inadequate to suppress the re completely.3.2. Water MistWater can be used in mines either in the form of spray or mist. McPherson (1993) mentioned that once a re has been progressed to a fuel rich condition thereis little chance of extinguishing without sealing off the re. He does, however, suggest that a means available to gain control of the re by the application of water as a natural scale fog.Water mist refers to ne water sprays in which 99% of the volume of the spray is in droplets with diameter less than 1,000 l. Water mist re suppression systems (WMFSSs) are readily available, simple in design and construction, easy to maintain, effectual in suppressing various res, non-toxic, and cheaper than other familiar re suppressing system with no harmful environmental impact.While applied in re areas, it cleans the air by dissolving soluble toxic gases produced during combustion, washing down smoke and suppressing dust, and thus improves visibility as well. Unlike many other re ghting systems, WMFSSs can be safely used in manned areas and found to be effective in open condition. Furthermore, water consumption in WMFSSs is far less than that in water ushing, spraying or sprinkling systems. On account of these advantages, much study has been carried out in recent years to develop appropriate WMFSSs to control various types and size of res.A survey carried out in 1996 indicated that nearly 50 agencies around the world were involved in the research and development of WMFSSs, ranging from theoretical investigations into extinguishing mechanisms and computer modeling to the development, patenting and manufacturing of water mist generating equipment . Water mist is being evaluated for the suppression of res in diesel fuel storage areas in underground mines at National Institute for Occupational Safety and Health (NIOSH), Pittsburgh. Water mist has shown a positive impact to control a fuel-rich duct re 30 when a series of experiments on water mist was carried out in a 30 cm square, 9 m long wind tunnel constructed in the Department of Mining & Minerals Engineering, Virginia Polytechnic Institute & State University. A re is called fuel-rich when the oxygen concentration falls to below 15%in products of combustion.The concept of water mist to suppress the mine re is a unique one and for the rst time in India it has been tried in the Mine Fire Model Gallery to work out the strategy to control re with the water mist in actual mining condition . For the purpose an indigenous system for generation of water mist has been developed.The water mist was infused in the gallery at a rate of 33 l/min. From the study the following points are emerged.After only 20 min of infusion of water mist on the full-edged re the temperature along the length of the gallery was reduced to a great extent. The average reduction of temperature was found to be 294C per hour. It also reduces the backlash to a great extent.It has been found that after application of water mist the oxygen concentration had increased to above 19% whereas the product of combustion gases (no measurable amount of methane) have decreased indicating retardation of combustion process.On application of water mist, reduction of generation rate of CO2 and CO was estimated as 89% and 93%, respectively.In the experiment with water mist hydrogen percent recorded an increase by 0.010.26% which is well below the explosive limit. Therefore, there was no formation of water gas (fuel gas containing about 50% CO, 40% H2, and small amounts of CH4, CO2 and N2) terminating the possibility of explosion.On application of water mist the opacity was decreased by 84%. Therefore, it can be inferred that the water mist has the potential to improve the visibility in the mines during open re condition.4. ConclusionBased on theoretical, experimental and eld observations the following points are emerged.1) Recent successful control of re with high-pressure high stability nitrogen foam in Indian coal mines and on open re experimentation in CMRI mine re model gallery has provided ample evidence that foam technology is a promising one.2) Water mist seems to have enough potential to control open mine re as has been observed on experimentation in CMRI mine re model gallery. It has several advantages. It reduces the temperature as well as Product of Combustion POC) gases particularly CO to a great extent. Further, it reduces the backlash nd SPM concentration thereby improves the visibility. There is no threat of ormation of water gas eliminating the chances of explosion.References1 R.P. Singh, I. Ahmed, A.K. Singh, S.M. Verma, B.C. Bhowmick A Model Experimental Gallery in India to Study Open Fire Dynamics in MinesIts Design and nstrumentation, in Proceedings of the 7th International Mine Ventilation Congress. racow, Poland, 1722 June, 2001, pp. 885892.2 S.K. Ray, A. Zutshi, B.C. Bhowmick, N. Sahay, and R.P. Singh, Fighting Mine Fires sing Gases with Particular Reference to Nitrogen, Journal of the South African Institute of Mining and Metallurgy, vol. 100(4), 2000, pp. 265272.3 A. Adamus, Review of the Use of Nitrogen in Mine Fires, Transactions of the Institution of Mining and Metallurgy, Section A, Mining Technology, vol. 111, 2002, pp.A89A98.4 R. Morris, A Review of Experiences on the Use of Inert Gases in Mine Fires, Mining Science and Technology, vol. 6(1), 1987, pp. 3769.5 T.V. Thomas, The Use of Nitrogen in Controlling an Underground Fire at Fernhill olliery, The Mining Engineer, vol. 123, 1964, pp. 311336.6 J.P.L. Bacharach, A.L. Craven, and D.B. Stewart, Underground Mine Fire Control ith Inerting Systems, CIM Bulletin, vol. 79, 1986, pp. 6772.7 S.P. Banerjee, Nitrogen Flushing in Coal mines as a Measure against Mine Fires, ransactions, Mining Geological and Metallurgical Institute of India, vol. 84(supplemento. 2), 1987, pp. 19.8 E.R. Wastell and G. Walker, The Use of Nitrogen in Fryston Colliery, The Mining ngineer, vol. 142, 1983, pp. 2736.9 CMRI S&T Report on Studies on Simulation of Open Fires in a Mine Gallery under aried Airow for Suppression of Fire and Explosions in Underground Coal mines, GAP/11/97, 116 pp.中文译文煤矿火灾控制的最近发展和实践S . K雷 R . P辛格中央矿业研究所，印度，丹巴德，恰尔肯德邦，826 001摘要：煤矿火灾严重威胁人们的财产和生命。防火的先进技术已经取得突破，例如火风压控制，注惰性气体或液体氮、动态压力平衡,矿井通风中风流逆转的应用,地下采空区的注泡沫、惰性、水雾等。文中对以上控制技术进行了详细的介绍，对世界各地区煤矿控制火灾的成功案例进行了报道。讨论了最近完成的一个关于各种的火压控制工艺,如注液体氮、注入高压高稳定性氮气泡沫,多组分细水雾在明火控制的科学技术项目。关键词：煤矿火灾、氮气泡沫、采空区惰性气体及水雾1简介一直以来,采矿被看作是最危险的日常活动。地下矿井工作面火灾的爆发的直接的威胁来自明火。此外,另一个无形的直接威胁来自一氧化碳中毒和爆炸,特别是高瓦斯煤矿。它会影响到工作人员在地下的时间,包括后续救援及消防工作。它不仅妨害煤炭生产,还会损失采煤机械。在煤矿火灾分成两组：(a)由煤自燃引起；(b)明火,由自然环境中的意外造成,由于点燃可燃材料。煤矿火灾通常是由如下原因造成的：风流停滞，进风和回风高压力差,采空区松散遗煤，电力、机械摩擦、爆破、焊接、爆炸和违规喝酒。2防火巷道模型为了理解明火发生的复杂动态现象(我矿井风流中的火灾通常从单一点的着火点开始)和各种控制火灾技术的有效性：例如液氮压制工艺,高压高稳定性氮气泡沫和水雾,最近印度丹巴德中央矿井水雾研究所设计和建造了一个矿井火灾模型的巷道。该模型巷道长65.5米;拱形，底宽2.4米,高2.7米。巷道的横截面是5.86平方米。巷道分为火区和无火区。抽出式轴流风机通风能力为25m3/ s .50mm高水柱的空气压入装置被安装在它的末端。这条巷道配备两部滑动门作为调节所需气流快速密封火区的移动风门。三维视图模型画廊如图1所示。它配备了最先进的计算机辅助在线远程控制系统。该系统由130个传感器(98个温度、3个压力、25个气体、2个热流密度、1个速度和悬浮微粒(SPM)浓度传感器)和数据日志记录器、电脑、电脑辅助设备等火灾连续监测的各种参数,如巷道内气体浓度(O2、CO2, CH4和CO,H2),空气流速、火区压力和风机压力、温度、热流密度、灰尘和微粒浓度。巷道内的结构细节及仪器系统在其他地方描述 1。长22米的实验火区巷道 (巷道开始10.50米)是用薄薄的一层从多不拉新建煤矿运来的煤板衬里,厚8 - 10厘米。固定的煤板和气体装置混合物用水泥和液体的粘合剂固定住。每一组实验用18 - 20吨煤。上文所有的控制措施,已被广泛应用于世界各地。在矿井火灾模型巷道中的明火的试验结果也进行了讨论。图1等距矿井火灾巷道模型3防火技术3.1高压泡沫注泡沫已经成功应用在矿山火灾救援中，在巷道中直接用水灭火是不可能的。USBM研究表明,泡沫中含水不应小于0.20公斤/立方米,否则泡沫不能够控制火势。足够的风力(大约8厘米高水柱)产生的泡沫可以能被运输到300米。泡沫对深部,快速推进,被埋或盲巷火灾似乎无效。在印度,用高压高稳定性泡沫抑制自燃热是一种新的、有效的方法。然而,这种方法已经被广泛地应用于控制捷克矿山长壁工作面自热。泡沫是由高压泡沫产生器的发泡气体的压力下产生的。所产生的泡沫由管道和消防水龙输送到火区。惰性气体(N2,二氧化碳)、压缩空气或两者的结合,作为泡沫气体。泡沫发生器由两个独立的单位即抽出装置和泡沫产生装置组成。泡沫是由水和5%的发泡剂组成的混合物。泡沫产生装置产生泡沫，再由抽出装置抽出形成混合物。同时惰性气体(N2)为泡沫发生器提供0.2兆帕的最低压力,泡沫混合物从喷嘴喷出,然后通过泡沫发生器内部安装的细网格。发泡单位的出口，阻燃水带的适用管径依据泡沫注入的运输方式。HPHS氮泡沫的发生系统被如图3。泡沫以如下方式控制自燃热：降低通过开采区域漏风降低温度煤形成薄泡沫降低吸附氧的速率在煤表面形成保护膜。高压氮气泡沫,最近已被应用于约翰约拉项目2号矿井的AW1长壁工作面，取得了令人鼓舞的结果。将这个矿井的泡沫注入长壁采空区围岩附近。一个推车上安装产量300 Nm3 /小时的PSA型氮发生器。高压高稳定性氮泡沫(HPHS)成本低(一公斤的发泡剂可以生产2立方米的泡沫，成本2.1美元)，使用寿命长。图3用于注入高压高稳定氮的设备HPHS氮气泡沫的速率为200立方米/小时，被应用在CMRI矿井火灾模型试验巷道控制开火。以下几点值得一提的。观察实验结果表明,温度显著降低。平均降低温度