O2/CO2与空气对燃煤汞形态分布的影响

为研究O2/CO2和空气燃烧方式对汞形态分布影响的差异，借助管式试验炉，对空气和O2/CO2 2种气氛下对4个煤种分别在600、800、1 000 ℃下进行了堆燃。燃烧过程中烟气的汞排放，采用Ontario Hydro方法进行吸收测试，比较了O2/CO2和空气气氛下的汞形态分布特点。试验结果表明，在相同温度下，与空气燃煤相比，煤粉在O2/CO2气氛下燃烧单质汞含量升高，二价汞含量降低。随着反应温度的升高，这两种气氛下单质汞的含量均逐渐降低，而二价汞的含量逐渐升高。同时在相同温度和反应气氛下，不同煤种汞形态分布不同，含硫量高的煤燃烧烟气中二价汞的含量比低硫量的煤高，而单质汞的含量比含硫量低的煤要低。而煤粉充分燃烧时，温度和煤种对于4种燃烧气氛下灰分中残留汞元素含量产生较小影响。

Effect of O2/CO2 and Air on Mercury Speciation in Coal Fired Flue Gases

To study the different effect of O2/CO2 and air atmospheres on mercury speciation, four coals were fired in a tube furnace in the above two atmospheres at 600,800 and 1000℃. Ontario Hydro method was used to identify mercury speciation in flue gases, and the characteristics of mercury speciation fired in air were compared with that in O2/CO2.The results show that more divalent mercury but less elemental mercury are produced when burned in air than in O2/CO2 atmosphere. The content of elemental mercury decreases and divalent mercury increases with temperature both in air and O2/CO2 atmosphere. When burned at same temperature and atmosphere, different coals have different effect on mercury speciation. For the coals with high sulfur content, more divalent mercury and less elemental mercury are produced in the flue gas than low sulfur content coals. If coals were fired completely, combustion temperature and coal type have no effect on mercury content resided in the ash for both air and O2/CO2 atmosphere.