CaO对煤中砷挥发性的抑制作用

RESTRAINING OF ARSENIC VOLATILITY USING LIME IN COAL COMBUSTION

在一定条件下CaO与As化合生成稳定的Ca3 (AsO4 ) 2 。模拟固定床燃烧试验 ,815℃下 ,CaO对煤中砷挥发性的抑制率范围在 3 0 5 %～ 37 35 % ,平均为 15 31% ,抑制效果明显。又进行了循环流化床燃烧试验 ,加入CaO后 ,砷在不同粒级流化床灰中的配置明显发生变化。细粒飞灰中砷含量明显降低 ,<0 0 30 8mm飞灰中砷含量从 172 8mg kg-1降至 17 6 7mg kg-1。烟道灰中砷含量降低 4～ 5 4倍以上。说明在煤燃烧过程中 ,一定温度条件下 ,CaO不仅可以固硫 ,而且对砷的挥发性也有明显的抑制作用。

WT4”BZ]Arsenic is one of the most widespread and most hazardous carcinogenic substances Coal combustion is the major source of arsenic in the atmosphere In this paper, it has been identified that lime can restrain the volatility of arsenic In fixed bed combustion of coal, the restraining rates of arsenic volatility are between 3 05% and 37 35% by using lime In circulating fluidized bed (CFB) combustion of coal, partitioning of arsenic changes markedly in ash with different size fraction between both with and without lime By using lime the content of arsenic in ash with particle size <0 0308mm decreases from 172 8 mg kg -1 to 17 67 mg kg -1 and that in ash from chimney decreases 4-5 4 times, too Restraining of arsenic volatility using lime is effective in coal combustion under certain temperature [WT4”HZ]