Characteristics of PM and PAHs emitted from a coal-fired boiler and the efficiencies of its air pollution control devices

  • Tang Wei Chen (???dataset.roles.dataset.creator???)
  • Jyh Cherng Chen (???dataset.roles.dataset.creator???)
  • Zhen Shu Liu (???dataset.roles.dataset.creator???)
  • Kai Hsien Chi (???dataset.roles.dataset.creator???)
  • Moo-Been Chang (???dataset.roles.dataset.creator???)



Sampling and analysis of filterable particulate matter (FPM), FPM<sub>2.5</sub>, condensable particulate matter (CPM), polycyclic aromatic hydrocarbons (PAHs), sulfur oxides (SO<sub>x</sub>) and nitrogen oxides (NO<sub>x</sub>) emitted from a coal-fired boiler equipped with selective catalytic reduction (SCR)+ electrostatic precipitator (ESP) + wet flue gas desulfurization (WFGD) + wet electrostatic precipitator (WESP) as air pollution control devices (APCDs) are conducted. The results show that NO<sub>x</sub> concentration emitted from the coal-fired boiler is 56 ± 2.17 ppm (with the NO<sub>x</sub> removal efficiency of 47.2%), which does not meet the best available control technology (BACT) emission standard (≤ 30 ppm). On the other hand, the WFGD adopted has a good removal efficiency for SO<sub>x</sub> and HCl. Both SO<sub>x</sub> and HCl emission concentrations are &lt;1 ppm, and removal efficiencies are &gt;99%. The FPM and FPM<sub>2.5</sub> emitted from the coal-fired boiler are 0.9 ± 0.06 mg/Nm<sup>3</sup> and &lt;0.09 ± 0.006 mg/Nm<sup>3</sup>, respectively. The overall removal efficiency of FPM achieved with ESP+WFGD+WESP+MGGH is 99.98%. However, high concentration of CPM (37.4 ± 6.3 mg/Nm<sup>3</sup>) is measured, which is significantly higher than FPM and FPM<sub>2.5</sub>. The concentrations of 27 PAHs at the WESP inlet and stack are measured as 667 ng/Nm<sup>3</sup> and 547 ng/Nm<sup>3</sup>, respectively while the removal efficiencies of gas- and solid-phase PAHs are 9% and 58%, respectively. The results show that APCDs adopted are not effective in removing PAHs (only 18%), and gas-phase PAHs contribute the most in the total PAH emission. In addition, the benzo(a)pyrene equivalent (BaP<sub>eq</sub>) concentration emitted from the stack is 28.8 ng-BaP<sub>eq</sub>/Nm<sup>3</sup>, and most of it is contributed by 4-6 ring PAHs with high toxic equivalent factors (TEFs). Furthermore, the emission factors of air pollutant emitted from coal-fired boilers equipped with different combinations of APCDs are compiled and compared. The results show that except for CPM and NO<sub>x</sub>, the emission factors of air pollutant calculated for this coal-fired boiler are lower if compared with other studies.
發行者Taylor & Francis