Environmental Operationcost Of Ultra-Low Emissions In Coal-Fired Power Plants

The increasingly serious environmental pollution dramatically affects our daily life.Coal is the main energy source of power plants in China,and thus it is also the main emission sources of atmospheric pollutants.To reduce SO2,NOx and soot discharged by coal-fired power plants has become the focus of atmospheric pollution control.At present,most of coal-fired power plants in China are equipped with desulfurization,denitration and dust extraction system,of which more than 90% of the desulfurization processes using limestone gypsum wet desulfurization process,denitration processes using boiler low NOx combustion modification +SNCR/SCR.Recently,with implementation of the new "Coal-fired power plant air pollutant emission standards" and the "Ultra Low Emissions" policy,coal-fired power plants in China started a new round of environmental renovation,including(1)desulfurization-efficiency improvement,by adding off plate,single tower double loop and double loop Twin Towers technology;(2)denitration-efficiency improvement,by improving the burner of the boiler and installation of SCR catalyst layer technology;(3)dust-extract-efficiency improvement,by adding dust collector,using low temperature electric dust collector,electric bag dust collector and wet electric dust removal technology.The ultra low emission improvement projects brought certain level of pressure to power plants,and the equipment operating cost and the pollutant reduction performance is a problem worthy of attention.This paper selected two 300 MW coal-fired units as the research object.The two units completed the desulfurization and denitration environmental renovation.In the last two years,the ultra-low emission transformation has been steadily processed.By analyzing the invenstment and operation data,the environmental protection equipment operating costs and the ultra low emissions of pollutants emission reduction performance before and after renovation has been obtained.Before the renovation of desulfurization,denitrification and dust-extract system,the operating costs of were 1.79 cents/kwh,1.07 cents / kwh,0.71 cents / kwh,a total of 3.57 cents / kwh;After the renovation,the operation cost of desulfurization,denitrification,dust were increased to 2.43 cents / kwh,1.09 cents / kwh,0.91 cents / kwh,a total of 4.43 cents / kwh,with an increase of 0.86 cents / kwh compared to before the renovationThe cost of the original desulfurization equipment for sulfur dioxide removal was 3134 yuan/ton,and the ultra low emissions of sulfur dioxide removal cost after the renovation is 6401 yuan/ton,with an increase of 104.24%.The new sulfur dioxide emission reduction cost is 23503 yuan/ton,which is 7.5 times than before the removal of the transformation.The cost of the original denitration equipment was 4921 yuan/ton,and the ultra low emissions of nitrogen oxide removal costs 4581 yuan / ton,with an increase of 955 yuan/ton,which is only 19.4% of the original cost.The original dust-extract equipment costs was 81 yuan/ton,and after the ultra low dust emissions after renovation,the cost is 113 yuan/ton,with an increase of 31 yuan/ton and 38.62%.The new smoke abatement costs 100009 yuan/ton,which is 1221 times than before the renovation.In the ultra low emission renovation project,the cost of nitrogen oxide emission reduction is basically the same,but the marginal cost of sulfur dioxide and dust extract reduction is too high.