In order to study the emission characteristics of mercury (Hg) from a 1 000 MW ultra-low emission coalfired power plant in China

the EPA Method 30B was used to sample the flue gas in different sites simultaneously.Moreover

solid and liquid samples

including the raw coal

bottom ash

fly ash

wastewater of desulfurization and wet electrostatic precipitator (WESP)

were also collected for analysis.The results show that

the mass balance rate of Hg was 96.65%

which is acceptable.The Hg in the flue gas mainly exists in three forms:particulate-bound mercury (Hg~P)

gaseous oxidized mercury (Hg~(2+)) and gaseous elemental mercury (Hg~0).The oxidation rate of Hg~0 across the selective catalytic reduction (SCR) denitraiton system was 45.47%.The electrostatic precipitator (ESP)had high Hg~P capture efficiency

at 98.88%.The wet flue gas desulfurization (WFGD) had high Hg~(2+)capture efficiency

at 98.10%.The removal efficiency of total Hg (Hg~T) by each air pollutants control device (APCD) was as follows:WFGD (60.13%)ESP (40.00%)WESP (38.95%).The removal efficiency of Hg~T by the system was 87.23%.The emission mass concentration of Hg~T in this study was 1.89μg/m~3

which has met the emission limits set by the ministry of environmental protection.