Experimental Study On Removal Of Elemental Mercury From Simulated Flue Gas With Biomass Activated Carbon

Mercury is a global pollutant which is volatile,mobility and biological enrichment,and which can be transmitted over long distances.Our country is a global power of mercury emissions,and coal combustion is the most important source of mercury pollution.Activated carbon injection technology?ACI?is considered to be a feasible technology for controlling mercury pollution in coal-fired power plants.Traditional activated carbon seriously hinder the development of ACI technology due to its high cost,low efficiency and poor selectivity.Therefore,the development of high efficient and cheap activated carbon is very important to the development of ACI technology.Biomass raw material are abundant in the north and production is huge.The cost of preparing activated carbon is low.In this paper,corn cob,peanut shell and cotton shell were selected as raw materials,and the optimum preparation conditions of activated carbon were selected by orthogonal method.Activated carbon was prepared by chemical activation method which ZnCl₂ was regarded as activator.The samples were characterized with BET,SEM-EDS,XPS.And the performance of mercury removal in simulated flue gas was evaluated.The mechanism of ZnCl₂ is analyzed in depth by some experiments.The results showed that ZnCl₂ was selected as an activator,and the mercury removal performance of the preparation of corn cob,peanut shell and cotton shell activated carbon were good.The average mercury efficiency in flue gas was about90%.In the flue gas analysis experiment,the adsorption capacity of activated carbon to NO and SO₂ was 140mg/m³ and 200mg/m³ respectively.Mercury removal efficiency was above 99%under Pure N₂.It still had a good removal mercury performance at high temperature?150??.By EDS and XPS characterization analysis shown that Zn and Cl were added on the surface of activated carbon.The preparation of activated carbon with ZnCl₂ was used to removal elemental mercury.Hg⁰ and Cl will have a chemical reaction at both inside and outside of the activated carbon which would react to generate HgCl₂,which was easily adsorbed on sample surface.By studying the mechanism of ZnCl₂,it could be speculated that Zn must act as an important role.