负荷适应性波纹板除雾器的结构特性研究

发布时间：2018-09-01 20:06

【摘要】：中电联的统计显示至2015年初,我国火力发电脱硫机组容量已超7.6亿千万,约占国家煤电机组装机总容量的92.1%,在脱硫机组之中利用湿法石灰石-石膏脱硫技术的机组容量占到了90%以上。在治理SO2的同时资源的消耗和对环境的二次污染问题日趋严重,脱硫烟气中含有的大量酸雾、石膏微粒以及少量其他的重金属微粒,如果不能有效去除,其将对下游设备造成腐蚀,对人体造成危害,甚至发生“石膏雨”或酸雨等环境污染。目前,电厂湿法烟气脱硫除雾器中的叶片都是固定安装的结构,并且多采用类型单一的折板式除雾器,折板式除雾器的分离效率有限,尤其对微米级及亚微观粒子几乎不能捕集、负荷适应性差等诸多弊端也日渐显现。本文针对大型燃煤锅炉脱硫装置中除雾器除雾效率不高、负荷适应性差、非智能化等问题开展研究。研究钩片的尺寸对除雾器性能的影响,以及最佳钩片尺寸结构和两级除雾器组合形式。作者对带钩折板式除雾器多种设计方案进行了模拟,以分析不同钩片尺寸对10~40μm液滴捕集的效果。又以湿法烟气脱硫系统中带钩波纹板除雾器为研究对象,采用数值模拟技术求解钩片直段长度、钩片圆弧段转折半径及钩片圆弧段转折角度等因素对除雾器性能的影响。首次基于钩片可调的除雾器,对吸收塔内烟气量与机组负荷、燃料成分等关系进行数学建模,重要辅机特性的关系式进行数据拟合,关联起机组负荷及燃料成分等参数与除雾器钩片的最优偏转角度,并在优化计算基础之上提出了除雾器的运行方法。结果表明:对折板式除雾器加装钩片,流场内的湍流程度得到加强,大幅度地提高了除雾效率。随着钩片长度的增大,气流的流动通道变窄,压降增大。随着钩片宽度的增大,大多数工况下,除雾效率和压降都是减小的。随着机组负荷的降低,除雾效率下降。采用改变钩片直段长度、圆弧段转折半径、圆弧段转折角度及钩片偏折角度能够对除雾器内气液两相流场进行调节,使之达到理想状态,提高了除雾效率。以典型30万千瓦单元机组湿法烟气脱硫系统作为算例,在40%~100%额定工况下,当使用设计煤种计算时,采用可调钩片方法,平均提高除雾效率4.1%。
[Abstract]:According to ITU statistics, by the beginning of 2015, the capacity of thermal power desulfurization units in China had exceeded 7.6 million. It accounts for 92.1% of the total installed capacity of the national coal motor unit. The capacity of the unit using wet limestone gypsum desulfurization technology in the desulfurization unit accounts for more than 90%. The problem of resource consumption and secondary pollution of environment is becoming more and more serious in the process of controlling SO2. A large amount of acid mist, gypsum particles and a few other heavy metal particles in desulfurized flue gas can not be removed effectively. It will cause corrosion to downstream equipment, harm to human body and even environmental pollution such as gypsum rain or acid rain. At present, the blades of wet flue gas desulphurization defroster in power plant are all fixed installation structure, and most of them adopt single type folding plate type mist eliminator, and the separation efficiency of folding plate type mist eliminator is limited. Especially for micron and submicroscopic particles, there are many disadvantages, such as poor load adaptability and so on. In this paper, the defogging efficiency, load adaptability and unintelligence of the demister in the desulfurization unit of large coal-fired boiler are studied. The influence of the size of the hook plate on the performance of the demister, the optimum size structure of the hook plate and the combination form of the two stage demister are studied. In order to analyze the effect of different size of hook plate on 1040 渭 m droplet trapping, various design schemes of baffled plate demister with hook are simulated in this paper. Taking the defogger with hook corrugated plate as the research object in the wet flue gas desulphurization system, the effects of the length of the straight section of the hook plate, the turning radius of the arc segment of the hook plate and the turning angle of the arc segment of the hook plate on the performance of the mist remover are solved by numerical simulation. For the first time, based on the adjustable hook mist eliminator, the mathematical modeling of the relationship between the smoke quantity in the absorber and the load of the unit, the fuel composition, and the data fitting of the important auxiliary machine characteristics are carried out. The optimal deflection angle between the load and fuel components of the unit and the hook plate of the demister is correlated, and the operation method of the demister is put forward on the basis of the optimization calculation. The results show that the turbulent degree in the flow field is strengthened and the efficiency of fog removal is greatly improved when the hook plate is installed in the folding plate type mist eliminator. As the length of the hook increases, the flow channel becomes narrower and the pressure drop increases. With the increase of the hook width, the defog efficiency and pressure drop are reduced in most cases. With the reduction of the unit load, the defogging efficiency decreases. By changing the length of the straight section of the hook, the turning radius of the arc, the turning angle of the arc and the angle of deflection of the hook, the gas-liquid two-phase flow field in the mist remover can be adjusted to achieve the ideal state and improve the efficiency of fog removal. Taking the wet flue gas desulfurization system of a typical 300000 kilowatt unit as an example, under the rated working conditions of 40% and 100%, the adjustable hook plate method is used to increase the average fog removal efficiency by using the adjustable hook plate method when using the design coal type calculation.
【学位授予单位】：东北电力大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X773

【参考文献】