淮南燃煤电厂锑的分配、富集与释放通量

The Distribution, Enrichment and Emissions of Antimony in Huainan Coal-fired Power Plant

锑是潜在环境有害元素,燃煤锑排放占中国大气锑排放总量的一半以上。因此,研究锑在电厂燃煤过程中的分配规律及富集模式对有效的锑减排政策具有重要意义。该文以淮南某电厂配有除尘脱硫装置的一个锅炉为例,通过3次全面的取样,发现煤炭在燃烧过程中,13%~17%的锑残留在底灰中;高达64%~68%的锑富集在飞灰中;脱硫产物中锑的占比较小,为3.7%~4.0%;最终排向大气的锑占比约为15%。静电除尘器对烟气锑的脱除效率较高,为77%~80%,接近世界平均水平,而湿法脱硫装置的除锑效率大约为20%。根据该研究得出的锑释放系数(0.14~0.18 g Sb/t coal),计算了整个淮南电厂锑的排放量。结果显示:淮南电厂燃煤锑的排放量从2003年的1.02 t,快速增加至2007年3.60 t(年增幅37%),然后缓慢增加至2010年的5.67 t(年增幅16%)。

Antimony is a potentially toxic element, and antimony emission from coal combustion accounts for more than half of total antimony emissions into atmosphere. Thus, effective antimony mitigation policy relies on the understandings of anti-mony distribution and enrichment during coal combustion in coal-fried power plants. In this study, we conducted three sam-pling campaigns in a utility boiler(equipped with electrostatic precipitator and wet flue gas desulfurization system) of Huainan coal-fired power plants, and measured antimony concentrations in feed coal and its combustion products. The results show that 13%~17% of antimony is retained in the bottom ash; as high as 64%~68% of antimony is concentrated in the fly ash; only3.7%~4.0% of antimony is contained in the desulfurization products; the remaining 15% of antimony is discharged into atmosphere. The calculated antimony removal efficiency of electrostatic precipitation is up to 77 %~80%, similar to the world average value, while the wet flue gas desulfurization system only has ~20% antimony removal efficiency. According to the antimony emission factor(0.14~0.18 g Sb/t coal), the antimony emissions of the whole Huainan coal-fired power plants are 1.02 tons in 2003, and increase sharply to 3.60 tons in 2007 and then slowly to 5.67 tons in 2010.