(299y) Mercury Emission Analysis of 1600-Mw Coal-Fired Power Plant by Ontario Hydro Method and on-Line Continuous Emission Monitoring

In this study, mercury (Hg) emissions from a coal-fired power plant with daily production of 1600 MW of electricity were analyzed. On-line mercury monitor was used to measure total Hg concentrations before and after various air pollutant control devices (APCDs), including selective catalyst reduction (SCR), electrostatic precipitation (ESP), and wet scrubber flue gas desulfurization (FGD). For the final stack gas, Ontario Hydro Method (OHM), which could measure oxidized (Hg2+) and elemental mercury (Hg0) concentrations separately, were used. Hg compound concentrations in exhaust gas mainly depend on 3 factors. They are types of fuel used, composition of the gas (e.g. HCl and SOx), and types of APCDs used. Hg concentration of the flue gas before and after SCR is 101 µg/m3 and 84 µg/m3, respectively. For post-ESP flue gas, it is 32 µg/m3. For the final stack gas after FGD, three trials were done with OHM. It has average Hg concentration of 1.27 µg/m3. Results clearly show that Hg content in flue gas decreases as it passes through various APCDs. By examining the data collected before and after all APCDs, total Hg removal efficiency is calculated to be 98.7%.