选煤厂给煤仓系统粉尘安全防控理论与技术研究

发布时间：2018-09-09 08:13

【摘要】：神华准格尔大型选煤厂年生产能力达24 Mt。由于原煤的易碎性和非亲水性、生产工艺装备流程的复杂性及其粉尘控制设备系统的不合理性等原因,导致选煤厂给煤仓系统煤尘浓度高达到550 mg/m3,煤尘污染十分严重。因此选煤厂给煤仓系统粉尘安全防控理论与技术研究不仅对于杜绝生产安全隐患,保障生产管理人员的身体健康及提高选煤厂管理水平均具有重要的现实意义。采用实验测试、理论分析和数值模拟相结合的方法,研究了准格尔选煤厂产尘环节粉尘运动的计算方法与基本规律；确定了给煤仓系统为粉尘防治研究对象,分析了选煤厂给煤仓系统煤尘特性与分布特征；分别基于给煤仓仓顶转载点、仓顶落煤过程、仓下给料系统中煤尘发尘机理、逸散规律的研究,提出了相应的控制技术；以仓顶转载点导料槽、给煤仓作为封闭空间,研究了的粉尘爆炸危险性与煤炭自燃危险性。给煤仓系统粉尘浓度与特性测定结果表明：治理前全尘、呼吸性粉尘分别超标1.5～27.5、1.82～8.43倍,呼吸性粉尘累计百分比约为54～67%,粉尘属于油性粉尘。利用诱导风流、牵引风流和空气冲击波风流等理论,研究了准格尔选煤厂给煤仓系统粉尘运移基本规律。分别采用稀疏相和稠密相模拟方法,建立了产尘点粉尘扩散基本方程和粉尘颗粒典型气固两相运动方程。运用气固两相流理论和空气冲击波理论,对导料槽长度及除尘器的安装位置进行了计算确定与优化,提出了给煤仓顶采用设置机头除尘器+仓间密闭罩+除尘器干式联合控尘技术、给煤仓下给料车间机尾无罩设导料槽+除尘器干式联合控尘技术。建立了给煤仓粉尘监控及自动喷雾系统。首次运用气固两相流、多孔介质渗流场与温度场耦合理论,对选煤厂给煤仓导料槽、给煤仓封闭空间内粉尘爆炸危险性与自燃危险性进行了分析,分析结果表明：导料槽内、给煤仓仓内粉尘浓度范围分别约为993-1016 mg/m3、2000～4500 mg/m3,均达不到煤尘爆炸下限浓度30000-50000 mg/m3,无爆炸危险性。煤仓内存煤高度为18.56m时,煤仓内存煤较少时,自燃风速出现在仓内煤的表面,仓内煤存在自燃可能性,提出了仓内煤自燃综合预防措施。存煤高度为25 m、45m时,不存在自燃危险性。
[Abstract]:Annual production capacity of Shenhua Zhunger large Coal preparation Plant reaches 24 Mt. Due to the friability and non-hydrophilicity of raw coal, the complexity of production process and equipment process and the irrationality of dust control equipment system, the coal dust concentration of coal bunker system of coal preparation plant is high to 550 mg/m3, coal dust pollution is very serious. Therefore, the theory and technology research of dust safety prevention and control in coal bin system of coal preparation plant is of great practical significance not only to eliminate the hidden dangers of production safety, to ensure the health of production managers and to improve the management level of coal preparation plant. Using the method of experimental test, theoretical analysis and numerical simulation, the calculation method and basic law of dust movement in dust production link of Zhungel Coal preparation Plant are studied, and the coal bin system is determined as the research object of dust prevention and control. The characteristics and distribution characteristics of coal dust in coal bunker system of coal preparation plant are analyzed, and the corresponding control techniques are put forward based on the research of the top transfer point of coal bunker, the process of top coal falling, the mechanism of dust generation and the law of dispersal of coal dust in coal bunker feeding system. The dust explosion risk and the coal spontaneous combustion risk were studied with the conveying tank at the top of the silo and the coal bunker as the closed space. The test results of dust concentration and characteristics of coal bunker system showed that before treatment, the total dust of respiratory dust exceeded the standard of 1.5 ~ 27.51.82% 8.43 times respectively, and the cumulative percentage of respiratory dust was about 540.67%, and the dust belonged to oil dust. Based on the theories of induced air flow, traction air flow and air shock wave, the basic law of dust migration in the coal bunker system of Zhungel Coal preparation Plant is studied. By using sparse phase and dense phase simulation method, the basic equation of dust diffusion at dust-producing point and the motion equation of typical gas-solid phase of dust particles are established. Based on the theory of gas-solid two-phase flow and the theory of air shock wave, the length of the guide tank and the installation position of the dust collector are calculated and optimized. The dry dust-control technology is put forward for the top of the coal bunker by setting the closed cover dust collector between the bunker and the dry dust-control technology of the dust remover without a guide groove at the tail of the feed workshop under the coal bunker. A dust monitoring and automatic spray system for coal bunker was established. The coupling theory of gas-solid two-phase flow, porous media percolation field and temperature field is used for the first time to analyze the dust explosion and spontaneous combustion risk in the feed bin of coal preparation plant and the closed space of coal bunker. The dust concentration ranges from 993 to 1016 mg/m3,2000~4500 mg/m3, in the coal bunker are below the lower limit of coal dust explosion (30000-50000 mg/m3,) and there is no explosion hazard. When the coal storage height is 18.56m and the coal stored in the bunker is less, the wind speed of spontaneous combustion appears on the surface of the coal in the bunker, and there is the possibility of spontaneous combustion in the coal in the bunker. The comprehensive preventive measures for the spontaneous combustion of the coal in the bunker are put forward. When the coal storage height is 25 m or 45 m, there is no danger of spontaneous combustion.
【学位授予单位】：辽宁工程技术大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TD714.4

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