2台600MW机组烟气中汞排放特性研究

Comparison of the Mercury Emission Level and Morphology of Flue Gases From Two 600 MW Units

采用Ontario-Hydro法和30B法对2台配备有不同SCR装置的600 MW级机组烟气中汞的存在形态及分布进行测试。从结果看,2台机组尾部烟气中汞排放浓度均小于5μg/Nm3,满足国家现行汞排放标准(低于30μg/Nm3)。2台机组分布在静电除尘器底灰和烟气中的汞差异较大,1号机组底灰中的汞含量占总量的77.6%,较2号机组高出一倍多。2号机组尾部烟气排放出口的汞平均含量占总汞输入量的46.7%,而1号机组尾气排放的汞含量仅占总汞输入量的9.6%。两者差异主要是由于1号机组烟气中飞灰吸附了较多烟气中汞,从而减少了气态汞排放。

By adopting the Ontario-Hydro method and the 30 B method,tested and measured were the morphology and distribution of mercury in flue gases from two 600 MW class units equipped with different SCR devices. It can be seen from the measurement results that both mercury emissions concentrations in the flue gases from the tail portions of both units are less than 5 μg / Nm3,meeting the national current mercury emissions standard 30 5 μg /Nm3. The difference between the mercury contents of the ash and flue gases at the bottom of the static precipitators of the two units is relatively big. The mercury content of the ash at the bottom of unit No. 1 takes up 77. 6% of the total mercury content,over one time more than that of unit No. 2. The average mercury content at the flue gas discharging port in the tail portion of unit No. 2 occupies 46. 7% of the total mercury input while that of unit No. 1 only accounts for 9. 6% of the total mercury input. The difference between both units is mainly attributed to the fact that the flying ash in the flue gases from unit No. 1 adsorbs more mercury in the flue gases,therefore,reducing the gas-state mercury emissions.