The combination control techniques of the pollutants generated in the coal-fired power plant

Abstract

At present, environmental issues are coming to the forefront in all parts of the global with increasing public concern. Coal is one of the most important primary energies in this world. Some pollutants such as SO2, NO x, Hg and other harmful matters are yielded during coal combustion. In china, coal holds up to 70% of consumption of the primary energy, and most of the power stations mainly adopt coal as the energy source, which induces much deterioration of the environment. To develop effective air pollution control techniques for coal-fired boilers is very important. Till now, scientists all around the world have developed various methods to reduce air pollution caused by coal combustion. Although the environmental situation has ameliorated, the pollutant emissions have not been completely eliminated. Some pilot projects have demonstrated that it is not economical to remove pollutants separately. There are several advantages to remove air pollutants simultaneously in a whole system, such as simplifying the controlling system, improving the operation characteristics, reducing the operating cost and so on. Many ways have been reported to remove the SO2, NO x and Hg from the flue gas, however, the combination control of air pollutants is rarely investigated. Besides introducing the hazards of air pollutants, and some techniques about desulfurization, denitration and mercury control methods, the paper summarizes the method to design the experimental devices of combination control, and the reasons to determine the experimental program and to select the adsorbents. The combination control scheme recommended in this paper is that spraying CMA (calcium magnesium acetate) into the furnace and increasing humidity at the end of the flue gas duct to take off SO2, NOx and Hg2+ simultaneously, applying the adsorption device of impregnating the zeolite with activated manganese dioxide as adsorbents to adsorb mercury, and using bag-house to capture fly ash to remove mercury.