电站燃煤锅炉烟气中颗粒物排放特性与脱除的数值模拟

发布时间：2018-01-16 07:03

本文关键词：电站燃煤锅炉烟气中颗粒物排放特性与脱除的数值模拟　出处：《上海电力学院》2014年硕士论文　论文类型：学位论文

【摘要】：目前影响环境质量的因素有很多，一些粒径小的细颗粒物是其中之一。这些细颗粒物，尤其是PM10、PM2.5等对人体的健康、全球气候变化有着不可推卸的责任。随着我国经济的迅速发展，用电负荷不断增加，燃煤电厂颗粒物的排放量逐年增加，因此国家对燃煤电厂颗粒物排放标准也日趋严格。本文通过对600MW燃煤发电运行机组状况细颗粒物排放的试验，根据电厂实际操作过程中采用不同煤种的情况，再结合电除尘器在给定不同负荷等条件下，对颗粒物排放特性进行分析，得到： (1)静电除尘效率随锅炉负荷的增加而降低，两者有着密不可分的关系； (2)当煤的水分、挥发分、固定碳波动范围不大时，，煤的灰分含量越高，除尘效率越低； (3)在利用粒度分析仪对电厂所采样品的处理，可清楚地看到各个电场分别对颗粒物的脱除情况以及对小于1μm颗粒物的捕集效果，从第一电场到第四电场的比例是逐级递增的，而对于粒径大于10μm的颗粒物，其效果正好相反。另外，还运用FLUENT数值计算软件，得到了细颗粒物在通过电除尘器前后的分布规律和变化特征，针对入口粉尘浓度、入口气流速度、电势电压和板间距的变化，与静电除尘器除尘效率的关系进行了系统地研究，得出:随电压(30-70kv范围内)的升高，除尘效率不断提高；除尘效率随入口粉尘浓度(5-20g/m3范围内)增大而降低；当流速较低时，随着流速的增加而增加，当大于某一值后，除尘效率随着流速的增加而降低；板间距在0.3-0.4m范围内，除尘效率随板间距的加大而提高，在0.4-0.5m范围内，除尘效率随其增大而降低。通过实验与数值模拟结果的对比，为今后静电除尘器的研究提供一定的依据。
[Abstract]:There are many factors affecting the environmental quality . The fine particles with small particle size are one of them . These fine particles , especially the PM _ ( 10 ) and the PM _ ( 2.5 ) , are responsible for the health of the human body and the global climate change . With the rapid development of our economy and the increasing electric load , the discharge amount of particulate matter of coal - fired power plant increases year by year , so the national emission standard of particulate matter in coal - fired power plant is also increasingly strict . Based on the test of fine particle emission of 600 MW coal - fired power generation operating unit , this paper analyzes the discharge characteristics of particulate matter under the conditions of different load and so on according to the actual operation process of power plant , and obtains : ( 1 ) Electrostatic precipitation efficiency decreases with increasing boiler load , which is closely related to both . ( 2 ) The higher the ash content of the coal , the lower the dust removal efficiency when the moisture content , the volatile component and the fixed carbon fluctuation range of the coal are not large ; ( 3 ) The effect of each electric field on the removal of the particulate matter and the trapping effect on the particles smaller than 1 渭m can be clearly seen in the treatment of the samples collected by the power plant by using the particle size analyzer . The effect of the particle size of the first electric field to the fourth electric field is gradually increasing , whereas for the particles with the particle size greater than 10 渭m , the effect is exactly the opposite . In addition , the FLUENT numerical calculation software is used to obtain the distribution and variation characteristics of fine particles before and after passing through the electrostatic precipitator . The relationship between dust concentration , inlet airflow velocity , potential voltage and plate spacing is studied systematically .

【学位授予单位】：上海电力学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：X773

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