| With the development of economy, the demand of power energy would increase greatly as well. However, the pollution from coal-fired power plant more and more and the environmental protection become very urgent. In the existing gas purification technology at home and abroad, the removal of dust, SO2, NOx and Hg0 were completed separately in different independent systems usually, and there is very few simultaneous and integrative processing. The study on simultaneous desulfurization, denitration and mercury removal from simulated flue gas was carried out in this paper. At the fixed-bed experimental system, the modified absorbents which have the performance of simultaneous desulfurization, denitration and mercury removal were selected to have an experimental study farther. The metheds such as SEM, EDS, XPS and chemical methods were used to analysis the absorbents and there byproducts. The mathematical model of mercury removal based on the fixed-bed were established and calculated. In addition, the experimental study and mass transfer kinetics of desulfurization, denitration and mercury removal in liquid phase were carried out. The study of this paper have certain theoretical meaning and application value for developing the technique of multiple pollutants simultaneous controlled from coal-fired flue gas.The modified absorbents which have the performance of simultaneous desulfurization, denitration and mercury removal was prepared by fly ash and CaO mainly. The analysis results of specific surface area and pore structure tests showed that the specific surface area and pore volume of fly ash increased about 10 times after digestion at certain hydrothermal condition by calcium oxide. Most of the micropore pore size were in the range of 3~40 nm, belonging to medium pore. The SEM and X-ray energy spectrum analysis showed that: the relative average content of Ca(OH)2 on the absorbents surface was higher than that inside. The additives were dispersed in the absorbent surface evenly.The effects of temperature, inlet mercury concentration, SO2 and NOx concentration on the mercury removal efficiency were investigated at fixed-bed experimental system. The effect of mercury in the flue gas on the simultaneous desulfurization and denitration was investigated also. The experimental results showed that the modified absorbents had preferable performance of simultaneous desulfurization, denitration and mercury removal from flue gas.The XPS analysis and chemical analysis results showed that the sulfur element in modified absorbent's byproducts mainly existed in the form of sulfate, and nitrogen element existed with nitrate and nitrite mainly, mercury element existed with ion-state. The mechanism of simultaneous removal of SO2, NOx and Hg0 by modified absorbents was discussed.The TCLP leaching experiment were adopted in the laboratory and the experiment results showed that the leaching amount of merury from byproducts lower than the standard of national and American EPA. These indicated that the byproduct could be used in water processing comprehensive utilization subsequently.Based on mass balance of mercury in the system and experimental data, adsorption macrokinetics models were developed to describe the adsorption characteristic of mercury from flue gas. The differential equations were established based on mass balance of mercury in the gas phase and solide phase. The model was solved using a Matlab program with a improved euler method process. The results showed that the experimental data were fitted to the simulation very well.The experiments of simultaneous desulfurization, denitration and mercury removal were carried out in NaClO2 solution. The effect of solution concentration, initial pH value, reaction temperature, concentration of SO2 and NO on the mercury removal performance was researched in the paper. The study showed that NaClO2 solution had a better performance of simultaneous removal of SO2, NO and Hg0 from flue gas. Based on mass transfer parameters of bubbled reactor measured by chemical method, mass transfer and reactor kinetics was studied after obtaining physical parameters and mass transfer coefficient. Some data, such as the absorption rate constant and enhancement factor of mercury removal in liquid phase, were calculated in the paper.
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