Research On The Characteristics Of Mercurv Emission And The Potention Of Emission Reduction In The Process Of Cement Production

The pollution of heavy metal mercury has been paid more and more attention all over the world.The cement industry is the third biggest source of mercury pollution after firing coal and nonferrous metal smelting in our country.In Cement Industrial Air Pollutant Emission Standards,the edition,2013,of which is the latest,the scope of gas pollutants has included mercury and its compounds,and determine the emission limit of mercury and its compounds is 0.05mg/Nm3(120mg/t cement),which indicates that China starts to control mercury pollution in the cement industry.Due to starting too late,there are many gaps in control technology and the control strategy.Doing research of the characteristics of atmospheric mercury emissions and emission reduction potential of the cement production line,are of great significance to grasp the basic situation of mercury pollution in China’s cement industry,implement the relevant control measures and introduce relevant policies.In the paper,test mercury and its compounds in flue gas discharge of the 11 different size of the typical cement production line and grasp atmospheric mercury emission factor and the speciation of different scale cement production line of mercury in flue gas to analyse the synergistic mercury removal capacity of the kiln dust remover,raw mill and SNCR.Through the simulation experiment,do some researches about the raw material grinding mechanism of synergistic mercury removal.The potention in future of atmospheric mercury emission reduction in cement industry was studied discussed.The emission factor of atmospheric mercury in cement production line in China is 65.33mg/t cement,and the amount of atmospheric mercury emission of cement industry in China is 153.39t in 2015.In terms of atmospheric mercury emission form,Hg0 is in the proportion of 60%;Hg2+ is in proportion 22.5%and the proportion of Hgp is 15.5%.The synergistic mercury removal efficiency of the raw mill is 84%at average,and effected by its form:the synergistic mercury removal efficiency of the average value is 37.15%for tube raw mill,and what is 72%for vertical raw mill.The average of synergistic mercury removal efficiency,the bag dust filter and electrostatic dust filter’s,is 63%and 35%respectively.Removal ability of dust collector on mercury is:Hg0>Hg2+>Hgp.SNCR is almost no interference on the cement production line of atmospheric mercury emissions,but the operation of SNCR is harmful for the flue gas mercury dust remover.At last,the potention in future of atmospheric mercury emission reduction in cement industry of existing equipment in cement production line is discussed in this paper.The results show that although the existing equipment has considerable potential for reducing emissions,it is still difficult to meet the needs of future mercury emission reduction in China,other technologies must be introduced,such as the activated carbon adsorption technology.