Assessment of the Costs of Implementing the Best Available Ash Collection Technologies at Coal-fired Thermal Power Plants

Abstract

According to existing plans, the environmental situation in Russia is going to be improved by modernizing or replacing outdated equipment at industrial enterprises and making a shift to the best available technologies. The thermal power industry is commonly referred to industrial sectors featuring the greatest negative impact on the environment. Emissions of fly ash with flue gases from coal-fired thermal power plants are of much significance from the viewpoint of atmospheric air pollution. Various ash removal technologies are used to reduce them, but a number of them are no longer able to provide the required quality of atmospheric air in areas experiencing a negative impact of thermal power plants. The aim of this work was to assess the possibility of using different types of ash collectors to fulfill the technological indicators of solid fuel ash emissions. For this purpose, the technical and environmental characteristics of various technologies for removing solid fuel ash from the flue gases of thermal power plants were compared, and their main indicators, advantages, and disadvantages were considered. The choice of the most effective ash collection technologies -- electrostatic precipitators and bag filters — to fulfill the technological indicators of ash emissions according to GOST R 50831-95 as the best available technologies is justified. A comparative technical and economic assessment of using electrostatic precipitators (EP) and bag filters (BF) downstream of the boilers of combined heat and power plants (CHPPs) and condensing thermal power plants (CTPPs) combusting the main Russian coals: grade SS Ekibastuz coal, grade SS Kuznetsk coal, grade 2B Irsha-Borodino coal, and Donetsk anthracite culm was carried out. The total capital and operating costs for the implementation, the specific costs for the removal of one ton of ash from different coals in EF and BF for pessimistic and optimistic inflation forecasts are determined. It is shown that an increase in inflation will have a very negative impact on the introduction pace of BATs at Russian thermal power plants and may slow down the introduction of bag filters, which are the most efficient BAT for ash collection. Recommendations on the use of electrostatic precipitators and bag filters at CHPPs and CTPPs for different types of coals have been formed. It is proposed to use bag filters in combusting high-ash coals, the ash of which is characterized by high electrical resistivity. Electrostatic precipitators should be used in combusting low- and medium-ash coals, because the difference in the mass of captured ash in the EF and BF for the same coal is small, whereas the cost of implementing EF is significantly lower. The specific cost of the ash removed differs little for the boilers of CHPPs and CTPPs operating on the same coal; however, it depends strongly on the level of inflation, the growth of which increases significantly the operating costs.