A Case Study of a Coal-Fired Power Plant about the Causes of Flue Gas Opacity
|關鍵字:||空氣污染控制;不透光率;粒狀空氣污染物;ESP;FGD;SCR;Air pollution control;Opacity;Particulate pollutant;ESP;FGD;SCR|
The thesis used the plume opacity model for the coal-fired power plant developed by the U.S. Electric Power Research Institute (EPRI) to investigate the causes of the opacity and its influencing parameters in a power plant in Taiwan. The study was based on the existing sampling and analysis data before and after the air pollution control devices were installed. When only the electrostatic precipitator (ESP) was installed, the contribution of the opacity by fine particles with the diameter less than 1 μm, coarse particles with the diameter greater than 1 μm and nitrogen dioxide was 23.3 ~ 31.6%, 41.0 ~ 49.5%, and 25.5 ~ 27.9%, respectively. By retrofitting the selective catalytic reduction (SCR) and the wet flue gas desulfurization (FGD) after the ESP, the contribution of the opacity by fine particles, coarse particles and nitrogen dioxide was changed to 77.7 ~ 86.2%, 8.0 ~ 13.1%, and 5.8 ~ 9.2%, respectively. This study found that by retrofitting the SCR and wet FGD, the particle concentration at the stack discharge was higher than the case when only the ESP was instualled. The majority of the particulate mass loading fell in 0.1~1 micrometer range, accounting for the majority of the opacity, 77.7~86.2%. Coarse particles, such as fly ash, could be removed by the wet FGD, but the by-products from the FGD could be carried over to the stack and increased the opacity. The concention of NO2 could be lowered by retrofitting the SCR, but the sulfite from the SCR catalyst and slipped NH3 could form condensible fine particles by nucleation and condensation effects of the wet FGD, resulting in an increase in the opacity of the flue gas.
|Appears in Collections:||Thesis|
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