摘要
针对目前我国煤矿防灭火技术和手段存在不足,特别是针对大范围采空区或巷道高冒火灾、采空区隐蔽火源及高位火源、综放及俯采工作面煤炭自燃防治的难题,提出了由粉煤灰(黄泥)、氮气和水组成的三相泡沫防灭火新技术,该技术可以利用煤矿已有的注浆系统将三相泡沫注入采空区并形成覆盖面广、可向高冒区堆积的泡沫体,能较好地充填采空区或高冒区,有效扑灭火灾.针对固体不燃物(粉煤灰、黄泥)、水和氮气三相介质的特性,成功研制出了使浆液具有较高发泡倍数和较长稳定时间的三相泡沫发泡剂.应用浮选动力学、表面化学、物理化学、热力学和流体机械等理论,较系统地提出了三相泡沫的形成机理.根据三相泡沫的特点,发明了三相泡沫发泡器。应用流体力学理论,建立了发泡器喉部至扩散段区域负压大小和浆液流量的方程关系式,并通过CFD流体力学软件模拟了三相泡沫发泡器内不同扩散角度下管内静压和浆液流速的分布状况,得出了扩散角为60°时的压力分布和流速是形成三相泡沫的最佳条件.开展了三相泡沫发泡剂溶液阻止煤自燃的试验研究,结果表明:三相泡沫发泡剂溶液对煤自燃的阻化效果显著,能有效地减缓煤的氧化放热速率,抑制煤温度的升高,同时也有效地抑制CO的释放量,是很好的防止煤炭自燃的阻化剂;三相泡沫的灭火性能试验表明,三相泡沫可在较致密的多孔介质中不同方向流动,渗透性强,流动范围广,可扑灭较大范围区域内的高位火源和隐蔽地点的火源.三相泡沫流变特性研究表明,含黄泥或粉煤灰颗粒的三相泡沫属于屈服假塑性非牛顿流体;试验考察了发泡倍数、浆液浓度、外界温度及气体介质对三相泡沫黏度的影响;建立了三相泡沫在水平管道中流动的数学模型,确定了三相泡沫发泡器在井巷中合理的安装位置;建立了三相泡沫在大空间中堆积高度的数学模型.在矿井灌浆系统中加入氮气,使泥浆发泡,体积增大,大流量的三相泡沫能在采空区中形成面与三维的流动方式,较之一般的水浆流动,覆盖面广,并可向上部堆积,能将更多的水、固体不燃物(黄泥、粉煤灰)带入防灭火区域,防灭火效果显著.建立了一套适合煤矿自然火灾防治的注三相泡沫的工艺系统,该系统安全可靠,操作方便,可连续大流量灌注.提出了沿顺槽采空区埋管、综采(综放)支架插管、地面打钻和与其它防灭火技术手段相互配合使用的多种注三相泡沫新工艺,并在现场得到了广泛应用.
It is difficult to deal with the fire in large area goaf, the top or undeterminated fire in goaf and spontaneous combustion of coal in slope and downward working face. Based on this, a new technology of three-phase-foam, which composed of fly ash or mud, nitrogen gas and water, was developed for mine fire control. The new technology grouts the three-phase-foam into the goaf covering wider area and accumulating to the high caving area using the existing grouting system. So the fire can be put out efficiently. According to the analysis on chemical elements, microstructure, phase compositions and water quality, a new foaming agent with high foam expansion and long stable time was developed successfully. The forming mechanism of three-phase-foam was obtained with the principles of thermodynamics, chemistry and hydrokinetics. Based on the characteristics of three-phase-foam, the foaming generator with high foam expansion was designed. Equation between flux of slurry and relative minus pressure in the distance of laryngeal to diffused segment was set up by Bernoulli＇s equation. Distributions of velocity and press in tube with different diffused angles were simulated by CFD software. The flow rate and pressure under 60°diffusion angle meet the condition of forming three-phase-foam well. Experiments were done to research the characteristics of three-phase-foam in preventing spontaneous combustion of coal. The results show that the preventing effect of three-phasefoam is remarkable. It can effectively depress the oxidation heat release rate, control the temperature of coal to rise and restrain releasing quantity of CO. The extinguishing experiments of three-phase-foam show that it can flow at different azimuth in compact porous media with strong penetrability and wide range, and can extinguish the top or undeterminated fire in goaf. The rheological properties of three-phase-foam with fly ash or mud were studied. It exhibits non-Newtonian behaviour and a characteristic of pseudo-plastic material. RheologicaI properties of three-phase-foam were studied experimentally in relation to shear rate, expansion of foam, temperature and gaseous medium. The right installation place of foaming generator was determinated according to the reduction of pressure in pipe of three-phase-foam. The mathematics model of accumulating in big space was set up, so the accumulating maximal height can be computed.
Slurry is frothed and its bulk expands when the slurry is added nitrogen gas in the grouting system. Three-phase-foam with expansion can flow in the three-dimensional fashion. It can cover with wider area, accumulate to the top and schlep more water and nonflammable granules into the goaf. A technologic system with the ability for preventing the spontaneous combustion of coal in mine was set up. The operational sytem is safe, reliable and convenient, it can grout with continuous flux. Many new technology of grouting three-phase-foam were put forward, for example, burying pipeline along airway, spiling pipeline at the back of brackets, drilling bores on the floor and matching with other technologies of controlling mine fire. These technologies are widely used in Chinese mines.
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2008年第4期585-586,共2页
Journal of China University of Mining & Technology
关键词
矿井火灾
煤炭自燃
三相泡沫
发泡剂
发泡器
mine fire, spontaneous combustion of coal, three-phase-foam, foaming agent, foaming generator
