Near-Zero Air Pollutant Emission Technologies and Applications for Clean Coal-Fired Power

Coal is the dominant energy source in China, and coal-fired power accounts for about half of coal consumption. However, air pollutant emissions from coal-fired power plants cause severe ecological and environmental problems. This paper focuses on near-zero emission technologies and applications for clean coal-fired power. The long-term operation states of near-zero emission units were evaluated, and synergistic and special mercury (Hg) control technologies were researched. The results show that the principle technical route of near-zero emission, which was applied to 101 of China's coal-fired units, has good adaptability to coal properties. The emission concentrations of particulate matter (PM), SO2, and NOx were below the emission limits of gas-fired power plants and the compliance rates of the hourly average emission concentrations reaching near-zero emission in long-term operation exceeded 99%. With the application of near-zero emission technologies, the generating costs increased by about 0.01 CNY.(kW.h)(-1). However, the total emissions of air pollutants decreased by about 90%, resulting in effective improvement of the ambient air quality. Furthermore, while the Hg emission concentrations of the near-zero emission units ranged from 0.51 to 2.89 mu g.m(-3), after the modified fly ash (MFA) special Hg removal system was applied, Hg emission concentration reached as low as 0.29 mu g.m(-3). The operating cost of this system was only 10%-15% of the cost of mainstream Hg removal technology using activated carbon injection. Based on experimental studies carried out in a 50 000 m(3).h(-1) coal-fired flue gas pollutant control pilot platform, the interaction relationships of multi-pollutant removal were obtained and solutions were developed for emissions reaching different limits. A combined demonstration application for clean coal-fired power, with the new "1123" eco-friendly emission limits of 1, 10, 20 mg.m(-3), and 3 mu g.m(3), respectively, for PM, SO2, NOx, and Hg from near-zero emission coal-fired power were put forward and realized, providing engineering and technical support for the national enhanced pollution emission standards. (C) 2020 THE AUTHOR. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company.