Mercury Emissions From Coal-fired Power Plants And Collaborative Law Control Technology

Mercury pollution caused by coal fired, following the PM, SO2, NOx, is one of the pollutants which should be strictly controlled by the coal-fired plants. Marking the control of mercury pollution having been put on the agenda is that it has been included in the binding targets control by our country’s newly revised GB13223-2011for the first time. To this end, our government exerts active efforts on the control of mercury emission. During the "Twelfth Five-Year" period, the point of our government is focused on the mercury abatement technology pilot and demonstration projects. Therefore, study on the coal-fired power plant mercury emission rules and emission reduction technologies has become an urgent task.This subject collects the latest research data and carries out a literature review at home and abroad on the tests of mercury precipitation and the control of mercury emission, based on which, research on the testing means and methods of mercury in coal-fired power plant has been carried out as well as a complete set of comprehensive sampling and analytical methods for accurately analyzing the mercury contents in solid by-products, desulfurization wastewater and flue gas in coal-fired power plants. Combined with the current development status of China’s power industry, this subject also selects typical domestic coals, typical pollution control facilities, typical crew-scale coal-fired power plants to do on-site testing, does research on the laws of the mercury emissions of coal-fired power plants in China and even proceeds an analytical research on the mechanism of cooperative control in mercury emission with existing pollutant-control facilities. The recommendations on increasing the mercury’s cooperative control of coal-fired power plant are proposed, as well.Through the study of this subject, it is found that the average mercury content of coals into the furnace is0.20μg/g in the measured power plants, which is closer to that0.22μg/g analyzed by Wang Qichao. Feasible study on making coal-burning by-products resourceful and useless should be actively pursued in owing to the higher mercury contents in the solid by-products of coal-fired power plants. In terms of the mercury contents in desulfurization wastewater far more than emission standard—mercury as the first class of pollutants0.05mg/L, which is stipulated in the "Integrated Wastewater Discharge Standard"(GB8978-2002), new desulphurization wastewater treatment process should be actively developed. According to our current mercury emission standards, the concentration of mercury in flue gas emissions of the measured unit, which could be discharged by most plants, however, is much higher than the background value for atmospheric mercury. Given that SCR removing NOx, ESP controlling particulates, WFGD capturing SOx of coal-fired power station, average mercury removal efficiency is up to83.42%, which indicates the feasibility and development prospects of using existing pollution control facilities to do cooperative control in mercury emissions.Through analysis of the flue gas mercury species before and after the existing APCDs in coal-fired power plants, this subject also studies the mechanism of all APCDs’cooperative control in mercury emission and proposes the cooperative control technology for efficient control in mercury emissions of coal-fired power plants.