600MW煤粉锅炉汞排放的试验研究

An Experimental Study of Mercury Emissions from a 600 MW Pulverized Coal-fired Boiler

为了评估大型燃煤锅炉汞排放水平，在对某600MW燃煤电站锅炉用煤以及燃烧产物烟气、飞灰、底渣在满负荷及70％左右负荷调峰运行时完成取样后，测定样品中的汞含量，通过研究不同工况下燃烧产物中汞的含量分布以及ESP（Electro tatic Precipitators）前后汞形态的变化等，获得了600MW煤粉锅炉汞的排放特性。试验发现600MW燃煤锅炉中汞主要以气态形式排出，烟气中气态汞的总量在4．99～14．79μg／m^3之间，且零价汞百分比含量较高，ESP前后气态汞形态变化不大．颗粒汞的脱除率达90％以上。

To evaluate the emission level of mercury from large-sized pulverized coal-fired boilers, the mercury content was determined from samples of coal, combustion product flue gas, fly ash and bottom slag taken from a 600 MW coal-fired utility boiler. The boiler has been operating at full load and also about 70% load under peak-shaving conditions. Through a study of the distribution of mercury content in combustion products under different operating conditions and of the change of mercury configuration before and after the ESP (Electro-static Precipitators) etc., the mercury emission characteristics of a 600 MW pulverized coal-fired boiler have been obtained. Through the experiments one can discover that the mercury in the 600 MW boiler has been emitted mainly in the form of gas with the total amount of gaseous mercury in the flue gas varying from 4.99 to 14.79 μg/Nm3. Moreover, the percentage content of zero-valence mercury is relatively high and there is little change in gaseous mercury configuration before and after the ESP. The removal rate of particle mercury amounts to over 90%.