300 MW燃煤电站砷、汞排放特征研究

摘要

An emissions studies for arsenic and mercury were conducted at a 300 MW coal-fired power plant.The solid streams such as coal,bottom ash and ESP ash were collected,and the arsenic and mercury in the flue gas around ESP were aslo directly sampled using Ontario Hydro Method and then tested.The results show that the arsenic concentration in fly ash is about 6.68×10-6,which is almost 2.5 times as that in coal,nevertheless that in bottom ash is only 1.70 ×10-6.Its concentration in the flue gas is 153.27 and 41.13 μg/m3 before and after ESP,respectively.The mercury concentration in coal,fly ash and bottom ash is about 2.5×10-7,1.9×10-7 and 1.5 × 10-7 respectively,its concentration in the flue gas before and after ESP was about 5.49 and 5.21 μg/m3.Arsenic is significantly concentrated in fly ash,whereas mercury is not.ESP unit has obvious synergistic effect on arsenic removal up to 71％,while it is not obvious for mercury removal.%对某300 MW燃煤电站煤、底灰和静电除尘器(ESP)飞灰进行采样并测定了其中的砷、汞含量,同时应用Ontario Hydro Method(OHM)标准方法和设备对ESP前后烟气中的砷、汞分布进行了直接采样和测试.对砷的检测结果表明,ESP 飞灰中砷含量约6.68×10-6,是原煤中砷含量的2.5倍左右,而底灰中砷含量仅为1.70×10-6,ESP前烟气中砷含量约153.27 μg/m3,ESP后砷含量急剧降低为41.13 μg/m3;对汞的检测结果表明,原煤中汞含量约2.5×10-7,飞灰、底灰中的汞含量分别约1.9×10-7、1.5×10-7;ESP前后烟气中总汞含量分别为5.49、5.21 μg/m3.砷在飞灰中明显富集,而汞在飞灰和底渣中均不具有富集效果.ESP单元具有明显的协同脱砷效果,平均脱除率约在71％左右,而对汞的协同脱除效果不明显.