Mercury Emissions from a Coal-Fired Power Plant and Their Impact on the Nearby Environment

Yee-Lin Wu,Li-Kai Tu,Yi-Chieh Lai,Shin-Je Lee,Dita Galih Rahmaningrum,Lin-Chi Wang,Guo-Ping Chang-Chien

doi:10.4209/aaqr.2012.04.0080

Abstract

This study investigated Hg emissions from a coal-fired power plant (CFPP) and their impact on the nearby environment. Atmospheric Hg concentrations were measured at sampling sites near a CFPP located in central Taiwan from November 2008 to March 2011. The mean gaseous and particulate Hg concentrations were 2.59–4.12 ng/m3 and 105–182 pg/m3, respectively, with gaseous Hg predominant at all sites (approximately 96% of the total atmospheric Hg). The seasonal variations of both gaseous and particle Hg concentrations in the atmosphere showed a similar pattern, with the highest concentrations in the cold season and the lowest in warm season. The mean emission factor of 13.1 mg/ton was found for the CFPP burning bituminous coal, with an electrostatic precipitator (ESP), flue gas desulfurization (FGD), and selective catalytic reduction (SCR) in series as air pollution control devices (APCDs). This figure was significantly lower than that measured at various power facilities, probably due to different fuel type, APCDs configuration, and flue gas condition. The modeling of the Industrial Source Complex Short Term (ISCST) revealed that the contribution of the CFPP to ambient atmospheric Hg was minimal (less than 1%).

Highlights

Mercury (Hg) compounds are highly toxic pollutants, and of great concern with regard to the global environment
The mean emission factor of 13.1 mg/ton was found for the coal-fired power plant (CFPP) burning bituminous coal, with an electrostatic precipitator (ESP), flue gas desulfurization (FGD), and selective catalytic reduction (SCR) in series as air pollution control devices (APCDs)
The CFPP is installed with a selective catalytic reduction (SCR) followed by ESP and wet FGD as APCDs, and the treated flue gas is emitted via a 250 m height stack

Summary

INTRODUCTION

Mercury (Hg) compounds are highly toxic pollutants, and of great concern with regard to the global environment. In Taiwan, coal-fired power plants account for approximately 32.1% of total electricity generation, based on 2010 statistics (MOEA, 2010). Both coal and fuel oil combustion generate emissions of persistent organic compounds, including polychlorinated dibenzo-p-dioxins and-furans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs), as well as many other major pollutants (e.g., particulates, carbon, sulfur, nitrogen oxides, and Hg) (Lin et al, 2007; Lin et al, 2010; Vega et al, 2010; Wang et al, 2010b; Xue et al, 2010; Bari et al, 2011; Chen et al, 2011; Tsai et al, 2011). The impacts associated with Hg emissions from a coal-fired power plant on the nearby areas were assessed based on the Industrial Source Complex Short Term (ISCST) model, and the annual Hg contribution to these areas was predicted

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS