Establishment of Emission Factor Database for Primary Aerosols of Chinese Coal-fired Power Plants

YU ZHAO (1,2), Shuxiao Wang (2), Chris. P. Nielsen (1), Xinghua Li (2), Jiming Hao (2)

(1) School of Engineering and Applied Sciences, Harvard University (2) Department of Environmental Science and Engieering, Tsinghua University

     Abstract Number: 549
     Last modified: May 13, 2010

Abstract
Field measurements and data investigations were conducted for developing emission factor database for primary aerosols of Chinese coal-fired power plants. Particulate matters (PM) with size distribution were measured using electric low-pressure impactor (ELPI) for 10 units in 8 coal-fired power plants over the country. The sampled PM from coal combustion displayed a bimodal size distribution, and the peaks for the submicron and coarse mode occurred at 0.2-0.3 and 2.0-3.0 micrometer respectively after dust collectors. Combing the results of field tests and literature surveys, the emission factors with 95% confidence intervals (CI) by boiler type, fuel quality and emission control device intervals were calculated with the Bootstrap and Monte Carlo simulations. The uncontrolled PM2.5, PM10 and total PM emission factors of pulverized boilers were estimated to be 0.4A (A, the ash content of coals, %), 1.5A and 6.9A kg/t with 95% CIs 0.3A-0.5A, 1.1A-1.9A and 5.8A-7.9A respectively, and the values were 0.032A (95% CI: 0.021A-0.046A), 0.065A (0.039A-0.092A) and 0.094A (0.0656A-0.132A) kg/t for electrostatic precipitator (ESP) controlled, and 0.0147A (0.0092-0.0225A), 0.0210A (0.0129A-0.0317A), and 0.0231A (0.0142A-0.0348A) for ESP plus wet flue gas desulphurization (wet-FGD) controlled respectively. For other dust collectors with less application in China, the PM2.5, PM10 and total PM emission factors were respectively 0.0019A, 0.0034A and 0.0042A for fabric filter (FF) and 0.135A, 0.291A and 0.479A for wet scrubber, without uncertainty ranges due to limited field measurements. Compared with US emission factor database (AP-42), PM emission factors for the units with ESP were generally higher than AP-42 values, resulting from the poorer removal efficiency of dust collectors. For units with advanced emission control technologies like FF, more field measurements are still needed in the future for reducing the emission factor uncertainties.