燃煤电厂湿法脱硫对PM2.5和多环芳烃排放的影响

INFLUENCE OF WET FLUE GAS DESULFURIZATION ON PM2.5 AND PAHs EMITTED FROM COAL-FIRED POWER PLANTS

采集了2个超低排放燃煤电厂湿法脱硫入口和出口的PM2.5样品,分析了PM2.5、水溶性离子和多环芳烃(PAHs)的排放规律。结果显示:电厂A和B脱硫出口的PM2.5浓度分别为(2.9±1.2),(3.4±2.0)mg/m^3,脱硫系统对PM2.5去除率分别为32.6%和34.6%;但PM2.5中水溶性离子浓度明显增加,主要离子组分为SO4^2-、Cl^-和NH4^+。厂区内大气环境的PM2.5浓度相比市区偏高34.8%,建议对厂区内无组织源加强管理。脱硫出口的PAHs质量浓度分别为(494.5±243.9),(563.2±310.3)ng/m3,脱硫系统对PAHs的去除率分别为52.7%和60.4%,且对中高环(5~6环)的PAHs去除效果要明显优于低环(2~3环)。WFGD系统前后烟气中的PAHs主要以中低环(2~4环)的组分为主,高环物种含量较少。

PM 2.5 samples were collected at the inlet and outlet of the wet flue gas desulfurization (WFGD) in two ultra-low emission coal-fired power plants in this paper.The PM 2.5 concentration, water-soluble ions, and polycyclic aromatic hydrocarbons (PAHs) emissions were analyzed.Results demonstrated that the PM 2.5 concentrations were (2.9±1.2),(3.4±2.0) mg/m 3 at the outlet of the WFGD in power plants A and B, respectively.The removal efficiencies of the WFGD system on PM 2.5 were 32.6% and 34.6% for power plants A and B, respectively.However, the water-soluble ions in PM 2.5 increased obviously.The main increased ions were SO4^2-, Cl ^-, and NH ^+ 4.PM 2.5 concentration in the atmospheric environment in power plant was 34.8% higher than that in the urban area.Therefore, the fugitive emission sources in power plant should be emphasized in the management.The PAHs concentrations at the outlet of the WFGD were (494.5±243.9),(563.2±310.3) ng/m 3.The removal efficiency of the WFGD system on PAHs were 52.7% and 60.4% for power plants A and B, respectively.The removal efficiencies on 5- and 6-ring PAHs were higher than 2- and 3-ring PAHs.The 2-, 3-, and 4-ring PAHs were the main components in the flue gas in the inlet and outlet of the WFGD system, while the 5- and 6-ring PAHs concentrations was comparatively lower.