摘要
燃煤电厂是我国当前最重要的大气汞排放源之一,而对于无烟煤电厂的研究不多。本研究通过安大略方法采集贵州省一座燃烧高灰无烟煤电厂的烟气,并同步采集煤炭、石灰石、底渣、飞灰、脱硫石膏等固体样品,对大气汞排放特征和汞质量平衡进行了现场测试。结果表明,锅炉类型和污染控制设施组合为煤粉炉+选择性催化还原脱硝+静电除尘+石灰石湿法脱硫的燃煤电厂,外排烟气汞平均含量为0.60μg·m-3,远低于国家燃煤电厂的汞排放标准30μg·m-3。由于煤炭灰分较高,导致该电厂汞在除尘前的烟气中主要以颗粒态为主,因此烟气中的大部分汞(84.57%)是通过静电除尘器脱除的,另外12.58%的汞是通过脱硫石膏脱除的,整个电厂的总汞脱除效率为97.15%,汞的排放因子为3.87 mg Hg·t-1煤,处于已有报道的较低水平。最终外排的烟气82.7%为Hg0,16.6%为Hg2+,0.8%为HgP。
Coal-fired power plant （CFPP） is one of the most important atmospheric mercury （Hg） sources in China, while studies on the burning anthracite coals of the CFPPs were inade- quate. In this study, we investigated the atmospheric Hg emissions and mass balance of a CFPP that burned high ash content anthracite coal in southwestern China. Flue gas was sampled with the Ontario Hydro Method （OHM） , and solid samples such as coal, limestone, bottom ash, fly ash, and gypsum were also collected. The CFPP is a pulverized coal （PC） boiler equipped with selective catalytic reduction （SCR）, electrostatic precipitator （ESP） and wet flue gas desulfu- rization （WFGD）. The results showed that total Hg content in the flue gas of the final discharging point was 0.60 μg · m-a, much lower than the national emission limit （ 30 μg · m-3 ）. Due to the high ash content in the flue gas, particulate bounded mercury were the main form in flue gas be- fore ESP, hence resulting in a high Hg removal efficiency through ESP. The total Hg removal ef- ficiency for this CFPP was 97.15%, of which, 84.57% was obtained by ESP, 12.58% through WFGD. The Hg emission factor of this CFPP was 3.87 mg Hg · t-I coal, which was at lower level among those previously reported. Among the Hg emitted from the CFPP 82.7% was in gaseous el- emental form （Hg2＋）, 16.6% in gaseous oxidized form （Hg2＋） and 0.8% in particulate bound form （ HgP ）.
出处
《生态学杂志》
CAS
CSCD
北大核心
2016年第5期1351-1357,共7页
Chinese Journal of Ecology
基金
贵州省环保厅环保专项项目
国家重点基础研究发展计划项目(2013CB430001)
国家自然科学基金项目(41373056)资助
关键词
燃煤电厂
无烟煤
汞排放
脱汞效率
coal-fired power plant
anthracite coal
Hg emission
mercury removal efficiency.
