| 燃煤电厂超低排放改造前后汞污染排放特征 |
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| 引用本文： | 宋畅,张翼,郝剑,刘更生,王家伟,安连锁,张永生.燃煤电厂超低排放改造前后汞污染排放特征[J].环境科学研究,2017,30(5):672-677. |
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| 作者姓名： | 宋畅 张翼 郝剑 刘更生 王家伟 安连锁 张永生 |
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| 作者单位： | 1.华北电力大学能源动力与机械工程学院, 北京 102206 |
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| 基金项目： | 国家科技支撑计划项目(2015BAA05B02) |
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| 摘 要： | 针对300 MW燃煤机组，基于US EPA(美国国家环境保护局)的30 B汞监测方法，通过多点监测对比了实施低氮燃烧器改造、SCR脱硝改造、新增低温省煤器、静电除尘器高频电源改造、湿法脱硫塔脱硫提效并增加管式除雾、新增湿式静电除尘器技术路线开展的超低排放改造前后汞排放及分布特征.研究表明:超低排放改造前，神华煤w(Hg)为49 μg/kg，烟囱入口ρ(Hg)测量值为1.87 μg/m3；煤燃烧及经过污染物控制单元后，有35.0%的汞存在于灰中，有29.5%的汞存在于石膏中，有35.4%的汞从烟囱排出.超低排放改造后，神华煤中w(Hg)为30 μg/kg，烟囱入口ρ(Hg)测量值为0.46 μg/m3；脱硫进水及湿式除尘器进水对汞平衡几乎没有影响，煤燃烧及经过污染物控制单元后，有36.1%的汞存在于灰中，有55.2%的汞存在于石膏中，有8.7%的汞从烟囱排出.超低排放改造后，污染物控制设备的烟气综合脱汞效率提高了1.5倍左右，表明超低排放脱硝增强了对汞的催化氧化，而脱硫增强了对二价汞的吸收结果.湿式电除尘器对脱汞没有明显效果.
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| 关 键 词： | 燃煤电厂 超低排放 汞排放 |
| 收稿时间： | 2016/8/24 0:00:00 |
| 修稿时间： | 2017/1/3 0:00:00 |
Mercury Emission Characteristics from Coal-Fired Power Plant Before and After Ultra-Low Emission Retrofitting |
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| Affiliation: | 1.School of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing 102206, China2.Sanhe Power Generation Co. Ltd., Langfang 065200, China |
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| Abstract: | Based on the 30 B mercury monitoring methods provided by the US EPA, mercury emissions and distribution of a 300 MW coal-fired power plant were compared before and after conversion to ultra-low emissions, which include retrofitting with a low NOx burner, SCR, ESP with high frequency power source, FGD with tubular mist eliminator and adding low temperature economizer and WESP. The mercury content of the coal was 49 μg/kg, and the mercury concentration at the stack entrance was 1.87 μg/m3 before retrofitting. After the air pollutant control devices, 35% of the mercury from coal combustion remained in ashes, 29.5% of the mercury in gypsum, and 35.4% of the mercury was discharged from the stack. After ultra-low emissions retrofitting, mercury content of the coal was 30 μg/kg, and the mercury concentration at the stack entrance was 0.46 μg/m3. After coal combustion and pollutant control devices, 36.1% of the mercury remained in ashes, 55.2% of the mercury in gypsum, and 8.7% of the mercury was discharged from the stack. After retrofitting, a big proportion was captured by APCD system compared with before retrofitting. The capture efficiency was increased 1.5 times. This might be due to the higher oxidation rate from elemental mercury to oxidized mercury in the SCR system and better capture of oxidized mercury in the WFGD system. WESP did not show any significant effect on the mercury capture efficiency. |
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| Keywords: | coal-fired power plant ultra-low emission mercury emission |
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