火电厂WESP细微颗粒物脱除特性分析与效率的数值模拟

发布时间：2018-01-02 22:30

本文关键词：火电厂WESP细微颗粒物脱除特性分析与效率的数值模拟　出处：《上海电力学院》2016年硕士论文　论文类型：学位论文

【摘要】：随着社会的快速发展,经济水平的不断提升,我国用电负荷不断上升,火电厂燃煤所导致的大气污染随之加重,特别是近年来频繁出现的雾霾不断引起社会公众的广泛关注。虽然干式静电除尘器在火电厂的广泛应用大大降低了颗粒物的总排放量,但是其对PM2.5、PM10等细微颗粒物的脱除效果并不理想。为满足国家对颗粒物排放的新要求,湿式静电除尘器(WESP)作为新型高效的除尘技术备受关注。本文对装备有湿式静电除尘器的典型660MW火电机组的颗粒物排放进行试验,对比了有无配置WESP时火电厂细微颗粒物脱除效果,并针对其实际运行过程中不同煤种、不同负荷情况时进行颗粒物的特性分析,WESP对火电厂细微颗粒物脱除效果显著,颗粒物排放浓度能够维持在3mg/m3以下,满足国家有关污染物排放标准的要求;WESP的颗粒物脱除效率与机组负荷和煤种都有一定的联系,WESP除尘效率随着负荷与煤种灰分含量的增加而降低;根据颗粒物排放特性的分析,WESP对30μm以下的细微颗粒物有着显著的脱除效果。通过采用数值模拟的方法对湿式静电除尘器细微颗粒脱除效率及其影响因素进行了研究。针对660MW机组WESP采用数值模拟计算的方法,构建湿式静电除尘器数学模型,探究喷淋水雾、气流速度、入口浓度、电势电压、喷淋水量等因素对细微颗粒物脱除效率的影响,得出:喷淋水对除尘效果的提升比较明显;WESP除尘效率随着气流速度(0.5m/s-3.5m/s)的增大而不断降低;当颗粒浓度(2mg/m3-300mg/m3)不断增加,除尘效率先随之增加,当大于30mg/m3然后基本保持平稳;除尘效率随着电势电压(10k V-50kV)的增加而不断提高;喷淋水量在0.05kg/s的条件下,WESP除尘效率可达到最高。同时对不同负荷条件下的WESP脱除情况进行模拟,结果与实际脱除情况对比,两者变化规律基本一致。
[Abstract]:With the rapid development of society and the continuous improvement of economic level, the power load of our country is rising, and the air pollution caused by coal-fired power plants has become more and more serious. Especially the frequent appearance of haze in recent years has attracted the attention of the public. Although the wide use of dry electrostatic precipitators in thermal power plants has greatly reduced the total emissions of particulate matter, but its PM2.5. The removal effect of fine particles such as PM10 is not ideal. Wet electrostatic precipitator (WESP), as a new and efficient dust removal technology, has attracted much attention. In this paper, the emission of particulate matter from a typical 660MW thermal power unit equipped with a wet electrostatic precipitator is tested. The removal effect of fine particles in thermal power plant with or without WESP is compared, and the characteristics of particulate matter are analyzed according to different coal types and different loads in the actual operation process. The effect of WESP on the removal of fine particulate matter in thermal power plant is remarkable, and the emission concentration of particulate matter can be maintained below 3 mg / m3, which meets the requirements of the national emission standards for pollutants. The removal efficiency of particulate matter of WESP is related to the unit load and coal type. The dust removal efficiency of WESP decreases with the increase of load and ash content of coal. According to the analysis of particulates emission characteristics. WESP has remarkable effect on removing fine particles below 30 渭 m. The removal efficiency of fine particles of wet electrostatic precipitator (ESP) and its influencing factors are studied by means of numerical simulation. The WESP of 0MW unit is calculated by numerical simulation. The mathematical model of wet electrostatic precipitator was constructed to explore the effects of spray water mist, airflow velocity, inlet concentration, potential voltage, spray water and other factors on the removal efficiency of fine particles. It is concluded that the effect of spray water on dust removal is obvious. The dust removal efficiency of WESP decreases with the increase of gas velocity (0.5 m / s -3.5 m / s). When the particle concentration increased from 2 mg / m 3 to 300 mg / m 3), the dust removal efficiency increased first, and then remained stable when the particle concentration was greater than 30 mg / m 3. The dust removal efficiency increases with the increase of potential voltage (10k V-50kV). The dust removal efficiency can reach the highest under the condition of spraying water at 0.05 kg / s. At the same time, the WESP removal under different load conditions is simulated, and the results are compared with the actual removal situation. The law of change between the two is basically the same.
【学位授予单位】：上海电力学院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM621.73

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