【摘要】 采用美国EPA推荐的汞浓度现场测试OHM取样方法,对300,MW和600,MW两燃煤电厂静电除尘器(ESP)和湿法脱硫装置(WFGD)前后烟气进行等速取样,采用Hydra AA汞分析仪测试烟气各种形态的汞质量浓度.结果表明:燃煤电厂烟气汞排放占总汞排放80%,以上;ESP能有效脱除烟气中的颗粒汞,同时还能脱除部分元素汞;WFGD对烟气中氧化汞的脱除效率达90%,以上,但对元素汞的脱除效果非常有限,原因是脱硫过程存在气相和液相的还原反应,将Hg2+转化成Hg0,出口烟气Hg0含量增加,导致总汞脱除效率降低.更多还原

【Abstract】 The Ontario hydro method(OHM)was used to sample flue gas before and after electrostatic precipitator(ESP)and wet flue gas desulfurization(WFGD)in two power plants of 300,MW and 600,MW,and various mercury concentrations were analyzed by Hydra AA. The result shows that mercury emissions of flue gas phase account for more than 80%, of the total mercury emissions from coal-fired plants;particulate mercury in flue gas could be effectively removed by ESP,and part of elemental mercury could also be removed;WFGD could remove more than 90%, of oxide mercury in flue gas,but its ability to remove elemental mercury is very limited. The reason is that the reduction reaction of gas and liquid phase exists in desulfurization process,in which Hg2+ was converted into Hg0,and the content of elemental mercury in outlet flue gas increased,leading to the decreased total removal efficiency of mercury.更多还原