| abstract |
An air preheater that preheats combustion air used in the exhaust gas treatment device, a heat recovery device that recovers exhaust gas heat from the air preheater outlet, a dust collector that recovers dust in the exhaust gas at the heat recovery device outlet, and a dust collector outlet A wet flue gas desulfurization device that removes sulfur oxides from the exhaust gas and a reheater that heats the exhaust gas at the outlet of the wet flue gas desulfurization device are sequentially arranged from the upstream side to the downstream side of the exhaust gas duct of the combustion device, A circulation line connecting the heat transfer tubes provided in the recovery unit and the reheater respectively is provided, and anhydrous sulfuric acid (SO 3 ) removal agent is supplied upstream of the heat recovery unit, and the exhaust gas temperature at the outlet of the heat recovery unit is dehydrated. Keep the dew point temperature below that of sulfuric acid. As the anhydrous sulfuric acid removing agent, at least one of an anhydrous sulfuric acid adsorbent, an anhydrous sulfuric acid reducing agent, and an anhydrous sulfuric acid neutralizer may be used. Thus, even when coal containing a large amount of sulfur is used as fuel, heavy metals in the exhaust gas can be effectively removed from the exhaust gas. |