Experimental Research Of Chemically Modified Silicate For Mercury Removal From Flue Gas

Recently,coal is still the principal part of our energy consumption.As lots of coal-fired power palant being built,the coal-fired emissions of trace elments pollution hace attracted wide attention.Now,in the"layout of heavy metal control"and"the twelfth five program"about the air pollution control of significant area have regulated the coal-fied emissitions of mercury.Therefore,It's urgent to control the mercury emissions from our national coal-fired power palant in the future.In this thesis,the background and methods about mercury control in the coal- fired power plant are introduced briefly at first.Next, the method of three mineral sobents (Kaolin,Bentonite,Zeolite)modification and there apllication on tarce elments removal are systermatically sumarized.The process of chemical modified mineral sobents are discribed and the physical/chemical characterizations of the mineral sobents are analyzed using X-ray fluorescence,Thermorgavimetric anlaysis, Scanning electron misciscope, etc.Furthermore, adsorption experiment of vapor pahse Hg~0 are carried out using chemically modified mineral sorbents and the affirmance experiment also carried out using atomic fluorescence mercury analyzer.Finally, the adsorption of Hg~0 on the surface of three mineral modified sobents are investigated using density functional theory (DFT) method.The experiment data indicated that the capability adsorption of Hg~0 by three non-modified mineral sobents is:Bentonite>Zeolite>Kaolin, the adsorption belongs to physisorptions.Compared the original sobents,the capability adsorption of Hg~0 increases after modified by KI,KBr,and the adsorption changes to chemisorption. The reaction tempreture,the quantity of sobents and KI,KBr have a strong influence on the adsoption of Hg~0.The mercury efficency improves as the reaction tempreture,the quantity of sobents increasing.The initial concentration of Hg~0 have non-influence on the adsorption experiment.The CVAFS and DTF method validates the experimental conclusion and the metal ion in the smectite may enhance the adsorption of Hg~0.