氯和灰分对大型燃煤锅炉烟气中汞形态的影响

采用安大略标准燃煤烟气汞采样分析方法,对大型燃煤锅炉出口烟气中汞形态的形成及分布机理进行了研究.分析了煤中Cl、灰分及采样位置对锅炉出口烟气中汞形态分布的影响.结果表明:烟气中的飞灰能够直接影响颗粒汞与气态汞之间的平衡比例;煤中灰分含量越多,锅炉出口烟气中颗粒汞所占比例越大;煤中Cl对气态汞中Hg0向Hg2 形态转变有促进作用;较高的烟气温度和较短的停留时间会严重阻碍飞灰对汞的吸附,影响颗粒汞的形成,同时也会阻碍Cl元素对Hg0的氧化作用.

Influence of Chlorine and Ash on Flue Gas Mercury Speciation of Large Scale Coal-Fired Boilers

Formation and distribution mechanism of flue gas mercury speciation of large scale coal-fired boilers were investigated using Ontario Hydro method.Influence of chlorine element and ash in coal,as well as sample positions on distribution of the flue gas mercury speciation were analyzed.Results show that fly ash can directly affect the proportion of balance between particle mercury and gas mercury in flue gas.The more ash content in coal,the more proportion of particle mercury in boiler flue gas.Chlorine element in coal can promote transformation of Hg~0 to Hg~(2 ) in gas mercury.High temperature and short residence time of flue gas can dramatically block mercury adsorption by fly ash and formation of particle mercury,as well as oxidation of Hg~0 by chlorine element.