Integrated assessment of the environmental and economic effects of an ultra-clean flue gas treatment process in coal-fired power plant

Abstract

China’s coal production and consumption levels rank first in the world. Coal-fired power plants currently account for 65.5% of the total electricity output of China’s power grid. Coal-fired thermal power is the main industry consuming coal in China and the main source of atmospheric pollutants. To alleviate environmental pollution, the Chinese government recently released stringent flue gas emission standards for coal-fired power units. These standards require that the emission of dust, sulfur dioxide, and nitrogen oxides does not exceed 10 mg/m³, 35 mg/m³, and 50 mg/m³, respectively, to achieve ultra-clean emissions. Life-cycle assessment and life cycle costing methods are combined to analyze and compare the environmental and economic effects before and after ultra-clean emission retrofit in a 315 MW unit. The environmental impact of flue gas processing for 1000 kWh power plants decreased from 0.1529 to 0.1295 after ultra-clean emission retrofit. Desulfurization and discharged flue gas after treatment are the key processes examined in this case study, while power consumption during desulfurization and residual mercury in flue gas are key substances. Therefore, looking ahead, decreasing power consumption in desulfurization and using mercury removal technology are important aspects for decreasing the environmental impact of flue gas treatment systems in coal power units.