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Coal combustion is one of the major cause of mercury emissions, mercury in the flue gas is often zero valent gaseous mercury (Hg0), gaseous divalent mercury (Hg2) and particulate mercury (HgP, refers to the attached mercury particles) kinds of patterns exist. Flue gas into the atmosphere, the zero-valent mercury can linger for a very long time, and can cause global mercury pollution through atmospheric diffusion. Existing flue gas purification device both certain mercury removal effect, but the effect of the different forms of mercury removal varied. Failure to increase the assistive technology, are difficult to achieve effective control of zero-valent mercury. Able to carry out the conversion of the zero-valent mercury in the flue gas direct gas-phase oxidation and catalytic oxidation method, which direct oxidation method has the advantages of low investment process is simple and broad interest. This paper focuses on the oxidizing agent used in the direct oxidation performance study. The first study, the oxidizing ability of the halogen simple substance of mercury, iodine, showed the strongest oxidizing second vapor of iodine reacts with mercury at a temperature of 373K, the reaction rate constant was 7.5 (± 0.3) x 10-17 cm3 of? molecules-1? s-1, the ratio of bromine in 3.5 (± 0.3) x 10-17 cm3 of? Molecules-1? s-1 is much higher. As the temperature increases, the mercury removal rate is gradually reduced, and the reaction is second order rate constant also becomes gradually smaller. NO gaseous reaction was strongly inhibited, while of SO2 Quedui surface reaction some inhibition. In the surface reaction, the speed increases to play a catalytic role. Under conditions contained iodine presence of activated carbon and fly ash, activated carbon has the best performance, the mercury removal efficiency of more than commercial Darco ?-Hg-LH. The existing conditions of fly ash, the role of activated carbon in an ordinary. Real flue gas, fly ash accounted for a large proportion, so the potential of the application is still very large. Then the study focused on the halogen compound, chloride, bromide, and compare it with bromine in the gaseous reaction oxidation capacity. When the concentration of bromine and bromine chloride, the oxidation capacity of the bromine chloride weaker in the bromine gas, However, when using the same moles of elemental bromine, bromine chloride the oxidation capacity was significantly stronger than the bromine gas. The combination of chlorine and bromine show some synergistic effect, in the case to achieve the same efficiency of mercury removal, the use of bromine chloride usage can save 30% of bromine. This phenomenon is also found in the presence of activated carbon surface reaction. Temperature and flue gas composition on the reaction, similar conclusions and halogen single quality. Finally, the activated carbon adsorption of mercury load bromine chloride, X-ray photoelectron spectroscopy (XPS) detector that activated carbon adsorption of elemental mercury is not a zero-valent mercury oxidation state of elemental mercury on activated carbon, and through changes in the binding energy of bromine and chlorine, initially speculated BrCl reaction mechanism. In addition, the experiment also investigated the chlorine oxidation of sulphides of mercury, compared with chlorine, both chloro sulfides have better oxidation performance of mercury of zero valent. The temperature rise of the same can inhibit the oxidation reaction of the two substances. Surface reaction in the presence of fly ash and activated carbon, so that the mercury removal efficiency greatly increased. In the presence of activated carbon, 8ppmv SCl2, mercury removal efficiency than commercial activated carbon Darco-Hg-LH. The component of NO in the flue gas was significantly suppressed the oxidation of mercury removal. When introduced in the reaction system, fly ash or activated after the influence of NO is not obvious. XPS analysis of the reaction product to fly ash combined of SCl2 with zero valent mercury detection. The results show that the oxidation of mercury adsorption on the surface of fly ash are oxidation state of zero valent mercury in simulated flue gas is oxidized. And halogen sulfide and zero valent mercury directly mixed by changing the mixing ratio to get a different product. Under certain conditions, SCl2 S2Cl2 the major product of the reaction with mercury HgS. Study the surface, using the above three types of oxidants to achieve well oxidized mercury removal and have good prospects for application, the necessary amplification experiments for further testing and evaluation.
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