【作者】 任万兴；

【导师】 王德明；

【作者基本信息】 中国矿业大学 ， 安全技术及工程， 2009， 博士

【摘要】 矿尘是煤矿生产中的主要灾害之一,它不仅造成尘肺病,而且会发生爆炸,导致重特大事故的发生,给矿工、企业和国家带来巨大的灾难和损失。目前矿山主要采用喷雾降尘技术,但该技术降尘效率低、喷嘴易堵塞和耗水量大。国外学者在上世纪50年代提出了泡沫除尘技术,但是至今国内外对该技术的研究还不够深入,其应用还不够广泛。为此,论文对煤矿井下泡沫除尘的理论与技术进行了系统研究,在泡沫的捕尘机理与除尘特性、发泡剂及泡沫除尘装置的研制、井下泡沫除尘工艺系统设计及应用等方面都取得了系列的成果。为给除尘泡沫的制备和应用提供理论基础,论文研究了泡沫除尘机理和除尘泡沫的基本性质。通过建立泡沫捕尘的理论模型,详细分析了泡沫捕尘的微观过程,提出了泡沫具有隔绝性能好、接触面积大、湿润速度快和黏附性能好的除尘特点。采用旋转粘度计测试了除尘泡沫的流变参数,指出除尘泡沫属于屈服假塑性流体,建立了泡沫流体的本构方程;研究了除尘泡沫的管道输运特性,根据除尘泡沫的状态方程,导出了泡沫在输送管道出口的膨胀倍数,定义了泡沫的压缩系数,给出了压缩系数与泡沫初始体积、膨胀后体积以及前后的压差三者之间的函数关系式;根据泡沫液膜的弹性和其抗变形能力成正比的原理,发明了一种测试除尘泡沫弹性的实验方法,并对除尘泡沫的弹性进行了实验测试与理论分析,研究了不同倍数和粉尘颗粒在液膜上的黏附对泡沫液膜排液的影响规律。为达到高效除尘的目的,论文采用Ross-Miles和水膜浮选两种实验方法,综合发泡和湿润两种性能,对数十种表面活性剂进行优选和复配,研制出了一种发泡倍数高、湿润能力强的除尘泡沫发泡剂。在上述研究的基础上,论文设计了泡沫除尘新工艺并研制了相应装备。根据粉尘产生及扩散机理,提出了除尘泡沫“集中发泡、多点除尘”的应用工艺;在充分分析国内外发泡器的原理及应用状况的背景下,以射流和涡流为理论基础,设计出了发泡器,并采用CFD技术对发泡器内部关键参数进行了模拟与优化。该发泡器内部没有运动部件,具备不堵塞、混合强度大、使用维护方便的优点;以管道内外泡沫的压缩与膨胀性能为理论基础,通过反复实验提出了泡沫喷头的设计原则,即喷头内部不能出现使泡沫流发生突变的结构,也不能靠撞击和挤压改变泡沫的流动方向,必须利用圆滑的导流边界使泡沫流线改变,充分利用泡沫的膨胀性能使其扩散。给出了喷头关键参数的确定方法,研制出了流量大、分布均匀和扩散角度大的喷头。在实验室构建了适应工业应用要求的大型泡沫实验系统,试验和验证了发泡剂、发泡装置及除尘泡沫的技术特性。将该技术在枣庄矿业集团新安煤矿新源12211轨顺掘进工作面进行了应用,现场测试结果表明泡沫对全尘和呼吸性粉尘的降尘效率分别是水雾除尘的2.11倍和1.72倍,有效地降低了井下采掘工作面的粉尘浓度,取得显著的防尘效果。该项技术的研究成果已申请7项专利,其中已获4项授权。更多还原

【Abstract】 Mine dust, one of the major hazards in coal mines, not only makes quantities of coal miners suffering from pneumoconiosis, but also results in serious dust explosion incidents and enormous economic losses. At present, many coal mines use the water spraying dust suppression technology, which is ineffective and easy to block nozzles, consumes a large amount of water. In 1950s, some researchers firstly proposed the foam dust control technique, with high efficiency and water resource saving, but there were many defects in application for the technology. In view of this situation, the author carried out related research on the theory and techniques for dust control by foam, then developed a set of technology and equipment, and a series of achivements were obtained,such as the mechanism and characteristics of dust capture by foam,foaming agents,the related equipment, the application process in underground mines and so on .In the thesis, in order to provide theoretical fundamentals for producing and utilizing of the foam. The author studied the mechanism for dust removal and the fundamental characteristics of the foam. By establishing the model for analyzing the dust capture process in microcosmic view, the model describes the regimes of the reaction between foam and dust in detail, then depicted comprehensively that the foam has a high efficiency in dust capture. When spraying on the dust generating points, the foam will cover these points without gaps; When spraying into the air with dust, foam has large volume and area; The foam film contains special foaming agents can increase the rate of wetting for dust; The foam with good viscosity, will quickly be adhered to sediment.The characteristic of foam’rheological dynamics was tested by rotary viscosimeter, it was pointed out that foam is shear-thinning non-Newtonian pseudoplastic fluid, then the constitutive equation of foam was derivated; The fluidal characteristics were studied by establishing mathematical model. Based on the state equations of the foam, the author deduced the expansion multiples in the outlet of pipelines, the compression coefficient ,and the quantitative relationship between the volume and pressure before and after the expansion; On the basis of direct proportion between elasticity and non-deformability of foam, a new testing method for elasticity was invented, then studied the elasticity of foam combining experiment and thory; Self-designed apparatus was used to study the effect of different multiples and dust particle sizes on the foam drainage.Inorder to inhence the efficiency of dust control by foam, the author worked out the high efficiency foaming agent. By using the Ross-Miles method and water film flotation method,which were combined with two main factors,foaming and wetting properties, the author screened and built foam agent from quantities of surfactantst, and worked out its adding proportion.The author designed the new application process and related equipment for dust control by foam. After analyzing of the foam generator around the world, the author put forward a new kind of foam generator, and used CFD to simulate and optimize the key parameters inside the generator. The generator has many merits such as strong mixing intensity, maintenance conveniently and nonclogging; Take the roadway head for example, the author studied on the dust generation and spread mechanism, and gave the application process principle, "Generate foam together, and remove dust in different points"; Based on a large number of experiments, it was concluded that the nozzle should avoid suddenly internal change, the smooth border line was used to change flow lines, as well as the expansion to make the foam spread. The internal structure of generator was also studied, with method been proposed to determine the key parameters of the nozzle, as a result, the nozzles, can get uniform distribution, with wide spread angle, and great flow rate.Building a laboratory experimental system which can simulate the conditions in underground mines, to test the performances of foam agent, foam generator and nozzle, then high-performance foams were produced. The foam dust control technology was applied in Zaozhuang Coal Mining Group Xinyuan 12,211 roadway head, the results showed that ,foam dust removal efficiency were 2.11 times and 1.72 times higher than water spray respectively, the new technology reduced dust concentration effectively, with great significance in dust control. Now the technology has been applied for six patents, three of which have been authorized.更多还原