The mercury migration and conversion characteristics of the lignite unit is not clear. The mercury concentration were measured by 30B method at five flue gas sampling points (before and after SCR, before low-temperature economizer, before and after desulfurization) in Inner Mongolia Guohua Hulunbuir Power Generation Co., Ltd. The emission concentration of mercury in the flue gas at the stack is 6.16, 4.53 and 2.98 μg/m3 at 319, 450, 550 MW, respectively. The emission concentration of mercury in flue gas decreases with the increase of unit load. In addition, the pollutant control devices have a synergistic effect on the mercury removal and the co-control efficiency is 31.48%, 29.68% and 66.65% at 319, 450, 550 MW. According to the mercury balance calculation, it can be found that after coal combustion, most of the mercury in the flue gas is discharged into the atmosphere (44.85%-65.27%), followed by fly ash (27.81%-51.15%) and gypsum (3.95%-14.61%). The fly ash test results indicate that the hardness value is between 0.28-7.15 GPa. The study results provide the basic data for further deep removal mercury from flue gas of coal-fired power plant.
