Experimental Study On Oxidation Of Elemental Mercury From Flue Gas By Diperiodatoargentate (?) Solution

With the continuous development of power industry,coal-fired pollution situation attracted widespread attention. Heavy metal mercury produced during the coal burning process, have serious harm to the environment and human health because of its high volatility and strong neurotoxicity. Therefor the removal of mercury from coal-fire flue gas has become an advanced research field, both in China and abroad. The <Emission standard of air pollutants for thermal power plants> issued by the ministry of environmental protection in 2011, even added the emissions limits of mercury at the first time, which means that power plant flue gas purification is about to enter the era of mercury removal.The paper reviewed the mercury content and existing form of coals in our country; the transformed morphology of mercury form coal-fire flue gas; the current situation of mercury emission, and also reviewed the latest mercury removal technology of power plants domestic and overseas, in addition analyzed advantages and disadvantages of each controlling technology, based on a plenty of literatures at home and aboard. And on the basis of previous research, the issue designed a liquid-phase oxidation process for mercury removal with a compound oxidants, which converted elemental mercury to oxidized mercury, and combined with FGD system to achieve the purpose of multipollution removal.Experiments simulate actual working condition. The removal efficiency of elemental mercury was researched, under this new oxidant technology. Both he optimum process conditions and the effect of different components of the flue gas to mercury removal were also been determined. The result shows that the optimum process conditions was the DPA concentration of 1.03 mmol/L, and the reaction temperature of 40 °C, and solution pH of 8.5. Initial Hg⁰ and O₂ concentration less impact on mercury removal; NO was found to have a promotional effect on Hg⁰ oxidation and removal when it was in low concentration, in contrast, SO₂ inhibited Hg⁰ oxidation and removal due to its competition for oxidant. Under the optimum condition, the The parallel tests of mercury removal were carried out, and the removal efficiency was 77.5%. The whole study can be a great basement for the using of power plant to removal the mercury of flue gas in practical application.