超低排放机组协同脱汞效益研究

Synergistic Mercury Removal Efficiency of Ultra-low Emission Units

采用安大略法对3台典型工艺路线的机组烟气汞浓度进行测试,研究超低排放机组汞排放水平和电除尘器、高效湿法脱硫装置、湿式电除尘器及烟气冷却器等污染物控制设备的协同脱汞效果。研究结果表明:超低排放改造后,燃用低汞煤的机组汞排放浓度为1.06~3.13μg/m^(3),总汞脱除效率为67.9%~88.7%;电除尘器的总汞脱除效率为24.5%~33.3%,其中颗粒汞和氧化汞的脱除效果较好,元素汞的脱除效率相对较低;湿法脱硫装置的总汞脱除效率主要取决于烟气中氧化汞的占比,测试机组脱硫系统总汞脱除率为52.6%~63.1%;湿式电除尘器的脱汞效率为59.2%,其中氧化汞具有较好的水溶性而几乎全部被脱除;烟气冷却器在回收冷凝水的同时,也有一定的协同脱汞效果。

Ontario method was used to test the mercury concentration in flue gas of three units with typical process route.This research work analyzes the mercury emission level of ultra-low emission units and the synergistic mercury removal efficiency by pollutants control equipment such as electrostatic precipitator,high-efficiency wet desulfurization unit,wet electrostatic precipitator and flue gas cooler.As the results show,the mercury emission concentration of the unit burning low mercury coal is 1.06-3.13 Mg/m^(3)and the total mercury removal efficiency is 67.9%-88.7%after ultra-low emission modification.The total mercury removal efficiency of electrostatic precipitator is 24.5%-33.3%,and the removal efficiency of particulate mercury and mercury oxide is better than that of elemental mercury.The total mercury removal efficiency of wet desulfurization unit mainly depends on the proportion of mercury oxide in flue gas.The total mercury removal efficiency of test unit desulfurization system is 52.6%-63.1%.The mercury removal efficiency of wet electrostatic precipitator is 59.2%,and almost all of mercury oxide is removed because of its good water solubility.The flue gas cooler has a certain synergistic effect of mercury removal while recovering condensate water.